Okay, so I need to figure out which compound among the options is C9H11NO2 based on the given IR and NMR data. Let's start by breaking down the information step by step.

First, the molecular formula is C9H11NO2. Let me check the molecular weights to see which options match. But maybe the functional groups can help more directly. The IR data shows medium to strong intensity bands at 3420 and 3325 cm⁻¹. Those are around the region for N-H stretching. Also, there's a strong band at 1720 cm⁻¹, which suggests a carbonyl group, likely from a ketone, amide, or ester. The 1H NMR has several signals: a triplet at 1.20 ppm (3H), a broad singlet around 4.0 ppm (2H), a quartet at 4.5 ppm (2H), and two doublets at 7.0 and 8.0 ppm (each 2H). 

Looking at the options:

A. Ethyl 4-aminobenzoate: The structure would be an ester (O-CO-O) with an amine group attached to the benzene ring. The ester group would have a carbonyl around 1720 cm⁻¹, which matches the IR. The NMR should show signals from the ester (OCH2CH3), the amine (NH), and the aromatic protons. The triplet at 1.20 ppm (3H) would be the CH3 group of ethyl. The broad singlet at 4.0 ppm (2H) might be the NH protons, but wait, in esters, the amine is usually a primary amine, which would appear as a broad peak. However, ethyl 4-aminobenzoate would have an NH2 group attached to the benzene, so the NMR would show a broad peak around 1-2 ppm for the NH protons. But here, the 4.0 ppm is a broad singlet for 2H. Then there's a quartet at 4.5 ppm (2H), which might be the OCH2 group adjacent to the ester. The aromatic region has two doublets at 7.0 and 8.0 ppm, each integrating to 2H, which suggests para-substituted aromatic ring with two sets of protons. Wait, but in 4-aminobenzoate ester, the substituents are at the 4 position (NH2) and the ester at the COO group. So the ring would have NH2 and COO at the para positions. The aromatic protons would be in the ortho positions, but wait, the ring would have two substituents (NH2 and COO-) at para, so the remaining aromatic protons would be in the ortho and meta positions relative to each substituent. Hmm, maybe the splitting would be different. Let me think. The aromatic protons would be two sets of two protons each, which could explain the two doublets. So the aromatic region in the NMR shows two doublets at 7.0 and 8.0 ppm, each integrating to 2H. That would fit a para-substituted benzene with two adjacent protons next to substituents. Wait, but in 4-aminobenzoate, the substituents are at para positions, so the ortho positions (relative to each substituent) would have the remaining protons. For example, if the substituents are at positions 4 (NH2) and the ester at position 1 (since benzoate ester is COO- attached to the benzene ring), then the aromatic protons would be at positions 2, 3, 5, 6. But how would the splitting look? Let me visualize the structure. The benzene ring has NH2 at position 4 and COOEt at position 1. Then positions 2 and 6 are adjacent to COOEt and positions 3 and 5 are adjacent to NH2. Wait, but in reality, the substituents are at positions 1 (COOEt) and 4 (NH2). So the adjacent positions would be 2 and 6 next to COOEt, and 3 and 5 next to NH2. So the protons at 2 and 6 would be ortho to COOEt and meta to NH2. Similarly, protons at 3 and 5 would be meta to COOEt and ortho to NH2. But in a para-substituted benzene with two substituents, the NMR would typically show two sets of doublets if the substituents are at neighboring positions. Wait, maybe I'm complicating this. The NMR shows two doublets at 7.0 and 8.0 ppm, each integrating to 2H. That suggests two sets of two equivalent protons each. So perhaps the aromatic ring has two substituents that split the ring into two pairs of equivalent protons. For example, if there's a para-substituent and another group that's ortho to it, but I'm not sure. Let me move on to the other options and come back.

Option B: 4-aminophenyl propionate. The structure would be a phenyl ring with an amino group at position 4 and a propionate group attached. Wait, no, 4-aminophenyl propionate would be the propionate ester of phenylamine. So the structure would be CH2CH2COO- attached to the benzene ring at position 1, with an amino group at position 4. Wait, but the molecular formula here would be C9H11NO2. Let me check. Phenyl group (C6H5) with an amino group (NH2) and a propionate group (CH2CH2COO-). Wait, that would be C6H5NHCOCH2CH2COO-. Wait, but that's a bit confusing. Alternatively, the structure might be Ph-CH2COO- with NH2 at position 4. Wait, no, the name is 4-aminophenyl propionate. So the propionate is the ester group. So the structure would be OCOOCH2CH2PhNH2. Wait, but molecular formula would be C6H5NHCOOCH2CH2. Let's count: C6 (benzene) + NH2 (adds N) + COOCH2CH2 (COO adds two O, and the CH2CH2 adds 2 C and 4 H). So total: C6 + COOCH2CH2 = C6 + 3 C (from COO and two CH2 groups) = C9. H: benzene has 5 H (since one H is replaced by substituents), NH2 contributes 2 H, COOCH2CH2 has 4 H (since CH2CH2 has 4 H), so total H: 5 + 2 +4 = 11. O: from COO (2 O) and ester O (another O?), wait, propionate ester is O-CO-O-? Wait, propionic acid is CH2CH2COOH, so the ester would be CH2CH2COO-R. So the ester group here is OCOOCH2CH2. Wait, no, the ester group is O-CO-O-, but attached to the benzene. Wait, no, the structure is Ph-O-CO-CH2CH2. Wait, no, the ester is R-O-CO-Ph. Wait, I'm getting confused. Let me clarify. The compound is 4-aminophenyl propionate. The "propionate" part is the ester, so the structure is Ph-CH2COO- with NH2 at position 4. Wait, but that would be 4-aminophenyl acetate, not propionate. Wait, maybe the structure is OCOOCH2CH2PhNH2. So the benzene has an amino group and an ester group. The ester would be O-CO-O- attached to the benzene. Wait, no, the ester group is O-CO-O- but attached to the benzene via the oxygen. So the structure would be Ph-O-CO-CH2CH2NH2. Wait, but that would have a benzyl group attached to the ester. Wait, maybe I'm overcomplicating. Let's think of the formula: C9H11NO2. If it's 4-aminophenyl propionate, then the benzene (C6H5) has an amino group (-NH2) and a propionate ester (-COOCH2CH2). So the ester group is O-CO-O- attached to the benzene. So the formula would be C6H5NHCOOCH2CH2. Let's count: C6 (benzene) + NH (1 N) + COO (2 O) + CH2CH2 (2 C, 4 H). So total C: 6 + 2 (from COO and CH2CH2) = 8? Wait, no. Wait, the propionate ester is CH2CH2COO-, so the propionate part is COOCH2CH2. So the entire structure would be Ph-CH2CH2COO-NH2? No, that's not right. Wait, maybe the structure is Ph-NH2-O-CO-CH2CH2. Wait, but that's not possible because the ester would be O-CO-O-, but attached to the benzene. I'm getting stuck here. Let me move on.

Option C: 3-ethoxybenzamide. Structure would be benzamide with an ethoxy group at position 3. Benzamide is Ph-CO-NH2. If there's an ethoxy group at position 3, then the structure is OCH2CH3 attached to the benzene at position 3, and the amide group at position 1 (if the numbering starts there). The molecular formula would be C6H5-CO-NH2 with an OCH2CH3 substituent. So the formula would be C6H5 (C6H5) + CO (C1O) + NH2 (N) + OCH2CH3 (C2H5O). Total C: 6 + 1 + 2 = 9. H: benzene (5 H) + CO (no H) + NH2 (2 H) + OCH2CH3 (5 H) = 5 + 2 +5 = 12. Wait, but the molecular formula given is C9H11NO2. So this option would have 9 C, but H would be 12, which is one more than the given formula. So this might not match. Also, the IR here: 3-ethoxybenzamide would have an ethoxy group (OCH2CH3), which would show a strong C-O stretch around 1000-1200 cm⁻¹, but the given IR has 3420 and 3325 (N-H) and 1720 (carbonyl). The NMR would have the ethoxy protons as a quartet around 1.2 ppm (3H), but the given NMR has a triplet at 1.20 ppm (3H). Wait, but ethoxy groups in NMR are usually quartets if next to the oxygen. Wait, ethoxy is OCH2CH3, so the CH3 would be a triplet (since the CH2 is next to O, which doesn't split the CH3), but the CH2 would be a quartet. Wait, no. Let me clarify. In ethoxy group (OCH2CH3), the CH3 is attached to the CH2. The CH2 would have two neighboring protons (from CH3), so it would split into a quartet. The CH3 would be adjacent to the CH2, so it would split into a triplet. So the ethoxy group would show a triplet (CH3) at around 1.2 ppm and a quartet (CH2) around 3.5 ppm. But in the given NMR, there's a triplet at 1.2 ppm (3H) and a quartet at 4.5 ppm (2H). So the quartet here is 2H, which doesn't match the ethoxy group. So option C's NMR doesn't match. Also, molecular formula doesn't match because H would be 12 instead of 11. So C is probably not correct.

Option D: N-(4-ethoxyphenyl)formamide. Structure would be formamide (HCONH2) attached to a phenyl group at position 4 with an ethoxy group. So the structure is Ph-OCH2CH3 attached to the formamide. Wait, no. The structure is HCONH- attached to a benzene ring with an ethoxy group at position 4. Wait, the formula would be C6H5-OCH2CH3 with NH2 and NH attached to the formamide. Wait, no, the structure is formamide (HCONR2), where R is the phenyl group. So the structure is HCONH-Ph-OCH2CH3. Wait, but the substituents would be at position 4 (ethoxy) and position 1 (formamide). Let me count the molecular formula. Phenyl group (C6H5) with OCH2CH3 (C2H5O) and NH2 (N). The formamide would be HCONH- attached to the phenyl. So total C: 6 (phenyl) + 2 (OCH2CH3) + 1 (from HCONH) = 9 C. H: phenyl (5 H) + OCH2CH3 (5 H) + NH2 (2 H) + H from formamide (1 H) = 5 +5 +2 +1 = 13. Wait, but the molecular formula is C9H11NO2. So this has 13 H, which is too many. So this doesn't match. Also, the NMR would have the formamide NH as a broad peak around 1-2 ppm. But the given NMR has a triplet at 1.20 ppm (3H) and a quartet at 4.5 ppm (2H). The formamide's NH would be a broad peak, but here the broad peak is at 4.0 ppm (2H), which might not match. Also, the ethoxy group's protons would be triplet and quartet, but in the given data, the quartet is at 4.5 ppm (2H), which could correspond to the OCH2 group adjacent to ethoxy. Wait, but in this structure, the OCH2 would be adjacent to the ethoxy group (OCH2CH3), so the OCH2 would be a quartet (4.5 ppm, 2H) and the CH3 would be triplet (1.2 ppm, 3H). That matches the given NMR. But the molecular formula here has too many H. Let's check again. Formamide is HCONH2. If it's N-(4-ethoxyphenyl)formamide, then the structure is Ph-OCH2CH3-NH-CO-H. Wait, no, the formamide is HCONH-Ph-OCH2CH3. Wait, but the molecular formula would be C6H5-OCH2CH3-NH-CO-H. Let's count C: 6 (C6H5) + 2 (OCH2CH3) + 1 (CO) + 1 (N) = 10 C? Wait, no. Wait, the formamide is HCONH-Ph-OCH2CH3. The HCONH group is -CONH2, but if it's attached to the phenyl and ethoxy, it would be HCONH-Ph-OCH2CH3. So the formula would be C6H5-OCH2CH3-NH-CO-H. Wait, that's C6 (from benzene) + 2 (OCH2CH3) + 1 (CO) + 1 (H from formamide) + 1 (NH2?) No, wait, formamide is HCONH2. If it's HCONH-Ph-OCH2CH3, then the NH is only one (since the other H is part of the HCONH). So the structure is HCONH-Ph-OCH2CH3. So molecular formula: C6 (Ph) + 2 (OCH2CH3) + 1 (CO) + 1 (N from NH) + 1 (H from HCO). Wait, let's count:

Ph: C6H5

OCH2CH3: C2H5O

CONH: C=O, N, H

Wait, the full formula would be C6 (Ph) + 2 (OCH2CH3) + 1 (CO) + 1 (N) + 1 (H from CONH). So total C: 6 +2 +1 = 9. H: Ph (5) + OCH2CH3 (5) + CONH (1) = 11. O: from OCH2CH3 (1) and CO (1) = 2. N: 1. So molecular formula C9H11NO2. That matches. So option D has the correct molecular formula. Now, the IR: strong band at 1720 cm⁻¹ suggests a carbonyl (maybe amide). The 3420 and 3325 cm⁻¹ are N-H stretches. In the NMR, the triplet at 1.20 ppm (3H) would be the CH3 of ethoxy. The quartet at 4.5 ppm (2H) would be the OCH2 group. The broad singlet at 4.0 ppm (2H) would be the NH protons. But wait, in formamide, the NH protons are usually a broad peak around 1-2 ppm, but here it's at 4.0 ppm. That might not match. Wait, maybe the NH is part of an amide. In an amide, the NH is usually a broad peak around 1-2 ppm. But in this case, the broad peak is at 4.0 ppm, which is more like an alcohol or amine. Hmm, this is confusing. Let me check the options again.

Wait, option D is N-(4-ethoxyphenyl)formamide. The structure would have an ethoxy group on the benzene ring, and the formamide group (HCONH-) attached to the benzene. But in this case, the NH group is part of the amide. The amide NH would typically show a broad peak around 1-2 ppm. However, the given NMR shows a broad singlet at 4.0 ppm (2H), which is higher than usual for amide NH. That might indicate that the NH is not part of an amide but perhaps a secondary amine. Wait, but the structure of D is formamide, which is an amide. So maybe this is a problem. Alternatively, perhaps the NH is part of a different group.

Wait, let's think again. If the structure is N-(4-ethoxyphenyl)formamide, then the amide group is HCONH-Ph-OCH2CH3. The NH in the amide would be a broad peak around 1-2 ppm, but the given NMR has a broad peak at 4.0 ppm. That doesn't match. So option D might not be correct.

Now, going back to the other options. Let's revisit option A: ethyl 4-aminobenzoate. The structure would be O-CO-O-CH2CH3 attached to the benzene at position 1, with an NH2 group at position 4. Let's check the molecular formula: C6H5-O-CO-O-CH2CH3 + NH2. So C6 (benzene) + O-CO-O-CH2CH3 (which is 3 C) + NH2 (1 N). Total C: 6 +3 =9. H: benzene (5 H) + O-CO-O-CH2CH3 (5 H) + NH2 (2 H) = 5 +5 +2 =12. O: from O-CO-O- (2 O) + ester O? Wait, the ester group is O-CO-O-. So two O from the ester. And the benzene has no O. So total O: 2. But the molecular formula is C9H11NO2. So H is 12 here, but given is 11. So this doesn't match. Also, the IR: the ester would have a carbonyl at around 1720 cm⁻¹, which matches. The N-H stretch at 3420 and 3325 would be the amine group (NH2). The NMR would have the ester OCH2CH3 as a triplet (CH3) at 1.2 ppm and quartet (CH2) at 4.5 ppm. The NH2 would show two broad peaks around 1-2 ppm. But the given NMR has a broad singlet at 4.0 ppm (2H), which would correspond to the NH2 group. However, the H count here would be 12, but the given is 11. So this might not fit. Also, the NH2 in the amide would be more deshielded than an ethyl ester. Wait, but in the ester, the amine is in the ortho position to the ester group. Maybe the splitting would be different. But the H count doesn't match.

Option B: 4-aminophenyl propionate. Structure would be Ph-CH2-COO-O-R? Wait, let me clarify. The name is 4-aminophenyl propionate. So the propionate group is attached to the benzene ring at position 4. Wait, the formula would be C6H5-CH2-COO-O-R? No, perhaps the structure is OCOOCH2CH2 attached to the benzene ring, with an amino group at position 4. Let's see: the benzene ring has NH2 at position 4 and a propionate group (CH2COO-) attached at position 1. The formula would be C6H5-CH2COO- + NH2. So total C: 6 (benzene) + 2 (CH2) + 2 (COO-) + 1 (NH2) = 11 C. Wait, but the molecular formula is C9H11NO2. So this doesn't match. Wait, maybe I'm miscalculating. Let's count again. Benzoate ester: the ester group is O-CO-O-CH2CH2. So the structure is Ph-O-CO-O-CH2CH2NH2. Wait, but that would be O-Phe-O-CO-O-CH2CH2NH2. Wait, that can't be right. Let me think again. The name is 4-aminophenyl propionate. The propionate ester is CH2CH2COO- attached to the benzene ring, with an amino group at position 4. So the structure is C6H5-CH2CH2COO-NH2. Wait, that would be a primary amine. Let's count the molecular formula: C6 (benzene) + 3 (CH2CH2COO) + 1 (NH2) = 6 +3 +1 =10 C. But the given formula is C9H11NO2. So that's one extra carbon. Maybe the structure is different. Alternatively, perhaps it's a secondary amine. Wait, the name is 4-aminophenyl propionate. The propionate ester is O-CO-O-CH2CH2 attached to the benzene ring, and the amino group is at position 4. So the structure would be Ph-O-CO-O-CH2CH2-NH2. Wait, but that would be diethyl phthalate derivative. Wait, molecular formula: C6 (benzene) + 2 (O-CO-O-) + 2 (CH2CH2) + 1 (NH2) = 6 +2 +2 +1 =11 C. But the given formula is C9. So this doesn't match. Therefore, option B is unlikely.

So, going back, the only option that matches the molecular formula is option D. But there's a discrepancy in the IR and NMR. Let's re-examine option D again. The structure is HCONH-Ph-OCH2CH3. The molecular formula is C9H11NO2. The IR shows 1720 (amide), which fits. The NMR shows a triplet at 1.2 ppm (3H) for CH3, quartet at 4.5 ppm (2H) for OCH2, and a broad singlet at 4.0 ppm (2H) for NH. But amide NH is usually around 1-2 ppm. So the broad peak at 4.0 ppm is suspicious. However, maybe the NH is part of an ethyl group. Wait, no. The structure has an amide group. Alternatively, perhaps the NH is a secondary amine. Wait, but the formula is C9H11NO2. If the structure is HCONH-Ph-OCH2CH3, then the NH is part of the amide. So the NMR should show a broad peak around 1-2 ppm. But here it's at 4.0 ppm. This discrepancy is confusing. Maybe the NMR data is for the ethyl group and the amide?

Wait, in the NMR data provided, there are four signals: triplet (1.20 ppm, 3H), quartet (4.5 ppm, 2H), doublets at 7.0 and 8.0 ppm (each 2H). Let's consider the triplet and quartet. The triplet (1.2 ppm, 3H) is likely the CH3 of the ethoxy group. The quartet (4.5 ppm, 2H) is the OCH2 of the ethoxy group. The broad singlet at 4.0 ppm (2H) could be the NH protons from the amide. But amide NH are usually broad but at lower ppm. However, if the amide is less strong (maybe a secondary amide), the NH could be around 4 ppm. Alternatively, maybe the NH is in a different environment. Let me check the structure again. If the structure is HCONH-Ph-OCH2CH3, then the NH is part of the amide. So the NH would be a broad singlet around 1-2 ppm. But here it's 4.0 ppm. So this doesn't match. Therefore, option D might not be correct.

Wait, but the molecular formula matches. So perhaps there's a mistake in the NMR interpretation. Let me look at the NMR again. The triplet at 1.20 ppm (3H) is likely the CH3 of ethoxy. The quartet at 4.5 ppm (2H) is the OCH2 of ethoxy. The broad singlet at 4.0 ppm (2H) is the NH in the amide. But if the NH is part of the amide, it shouldn't be at 4 ppm. Maybe the NH is part of a different group. Alternatively, perhaps the NH is not part of the amide but a secondary amine. Wait, but the structure in D is N-(4-ethoxyphenyl)formamide, which is an amide. Hmm.

Alternatively, perhaps the structure is N-ethyl-4-aminobenzoate. Wait, no, that's option A. Let me check option A again. Option A: ethyl 4-aminobenzoate. Structure would be O-CO-O-CH2CH3 attached to the benzene ring, with NH2 at position 4. The formula would be C6H5-O-CO-O-CH2CH3 + NH2. So total C: 6 (benzene) + 3 (COOCH2CH3) + 1 (NH2) =10 C. But the given formula is C9. So that's one extra carbon. Therefore, option A is out. So back to option D. Perhaps the NMR data is not matching, but the molecular formula and IR do. Alternatively, maybe the structure is different.

Wait, another possibility: the structure is N-ethyl-4-aminophenyl propionate. Wait, but that's not one of the options. Let's think again. Maybe the structure is ethyl 4-aminobenzoate. Let's recalculate the formula. Ethyl ester: O-CO-O-CH2CH3. Benzene ring with NH2 at position 4. So formula would be C6H5-O-CO-O-CH2CH3 + NH2. So C: 6 (benzene) + 3 (COOCH2CH3) + 1 (NH2) =10 C. But the given formula is C9. So that's not matching. Therefore, option A is out.

Wait, perhaps the structure is ethyl phenyl propionate. But that's not an option. Let's think again. Maybe the structure is phenyl acetate with an ethoxy group and an amine. Wait, but the options don't include that. Let me see the options again.

Option D: N-(4-ethoxyphenyl)formamide. The structure is HCONH-Ph-OCH2CH3. The formula is C9H11NO2. The IR: 1720 cm⁻¹ (amide), 3420 and 3325 cm⁻¹ (NH from amide). The NMR: triplet (CH3), quartet (OCH2), and broad singlet (NH). But the NH should be at lower ppm. However, maybe the amide is less strong, making the NH shift upfield. Alternatively, perhaps the amide is part of a different structure. Alternatively, perhaps the structure is an ethyl amine attached to a propionate. But that's not an option.

Alternatively, maybe the compound is 4-aminophenyl acetate ethyl ester. Wait, but that's not an option. Let me check the options again.

Wait, option B: 4-aminophenyl propionate. Structure would be Ph-CH2-COO-O-R? Wait, maybe the structure is OCOOCH2CH2 attached to the benzene ring with NH2 at position 4. The formula would be C6H5-CH2-COO-O-R + NH2. Let's count: C6 (benzene) + 3 (CH2COO-) + 2 (O-R) + 1 (NH2) =6+3+2+1=12 C. But the formula is C9. So that's not matching. Therefore, option B is out.

Option C: 3-ethoxybenzamide. Structure would be benzamide with ethoxy at position 3. So OCH2CH3 attached to the benzene at position 3, and the amide group at position 1. The formula would be C6H5-OCH2CH3 + CONH2. So C:6+2+1+1=10 C. But the formula is C9. So that's out.

So the only option that matches the molecular formula is option D. But the NMR discrepancy remains. Let me check the NMR again. The triplet at 1.2 ppm (3H) is ethoxy CH3. The quartet at 4.5 ppm (2H) is ethoxy OCH2. The broad singlet at 4.0 ppm (2H) is likely the NH from the amide. But amide NH is usually around 1-2 ppm. So maybe the amide is not present. Alternatively, perhaps the structure is different. Wait, maybe the compound is ethyl 4-aminobenzoate with an ethoxy group. Wait, that's not an option. Let me think again.

Wait, maybe the structure is ethyl 4-aminobenzoate with an ethoxy group on the benzene. Wait, but that's not an option. Let me check the options again. The options are:

A. ethyl 4-aminobenzoate

B. 4-aminophenyl propionate

C. 3-ethoxybenzamide

D. N-(4-ethoxyphenyl)formamide

So the only option with correct formula is D. But the NMR doesn't match. Unless the NH is not part of the amide. Wait, maybe the structure is ethyl 4-aminobenzoate with an ethoxy group. Wait, but that's not an option. Alternatively, maybe the structure is ethyl 4-aminobenzoate with an ethoxy group attached to the ester. Wait, that would be ethyl 4-aminobenzoate with an ethoxy ester. But that's not an option.

Alternatively, maybe the structure is ethyl 4-aminobenzoate with an ethoxy group on the oxygen of the ester. Wait, that would be ethyl 4-aminobenzoate with an ethoxy ester. But that's not an option. Let me think again.

Alternatively, perhaps the structure is phenyl acetate with an ethoxy group and an amine. But that's not an option. Let me check the options again.

Alternatively, perhaps the structure is ethyl phenylacetate with an ethoxy group and an amine. But that's not an option.

Wait, maybe the structure is ethyl 4-aminobenzoate with an ethoxy group on the benzene. But that's not an option. Let me check the molecular formula again for option D. C9H11NO2. The structure is O-CO-O-CH2CH3 attached to the benzene (C6H5), and NH2 at position 4. Wait, but that would be ethyl 4-aminobenzoate, which has formula C9H10NO2 (since C6H5 (5 H) + O-CO-O-CH2CH3 (5 H) + NH2 (2 H) = 5+5+2=12 H? Wait, no. Wait, ethyl 4-aminobenzoate would be O-CO-O-CH2CH3 attached to the benzene (C6H5), and NH2 at position 4. So the formula would be C6H5-O-CO-O-CH2CH3 + NH2. C:6 +3 (COOCH2CH3) +1 (NH2) =10 C. But the given formula is C9. So that's not matching. Therefore, option A is C9H11NO2, but the formula for option A would be C10. Wait, perhaps I made a mistake earlier.

Wait, the molecular formula for ethyl 4-aminobenzoate is C9H10NO2. Let me check: benzene (C6H5) + O-CO-O-CH2CH3 (3 C) + NH2 (1 N). So total C:6+3+1=10. Wait, no. Wait, ethyl ester is O-CO-O-CH2CH3, which is 3 C. Benzene is 6 C. NH2 is 1 N. So total C:6+3+0 (NH2 doesn't add C) =9 C. H: benzene (5 H) + O-CO-O-CH2CH3 (5 H) + NH2 (2 H) =5+5+2=12 H. O: from O-CO-O- (2 O) and any others? No. So molecular formula would be C9H12NO2. But the given formula is C9H11NO2. So that's one H less. Therefore, option A would have C9H12NO2, which doesn't match the given formula. So option A is out.

Therefore, the only option that matches the molecular formula is option D. But the NMR doesn't match. However, perhaps there's a mistake in the NMR interpretation. Let me think again. The NH in the amide is usually broad around 1-2 ppm. But here it's at 4.0 ppm. Maybe the amide is part of a different structure. Alternatively, perhaps the amide is not present. Wait, but option D is formamide. So the structure must have the amide group. Therefore, the NMR should show a broad peak around 1-2 ppm. But here it's at 4.0 ppm. This discrepancy is confusing. However, since the molecular formula and IR match, and the NMR is the only one that provides specific data, perhaps there's an error in the NMR. Alternatively, maybe I missed something.

Wait, let me check the NMR again. The triplet at 1.20 ppm (3H) is ethoxy CH3. The quartet at 4.5 ppm (2H) is ethoxy OCH2. The broad singlet at 4.0 ppm (2H) is NH. But if the NH is part of an amide, it should be around 1-2 ppm. However, in some cases, the NH of a secondary amide might shift upfield. Maybe in this case, the amide is not primary. Alternatively, perhaps the NH is part of a different group. Wait, but the structure is formamide, which is a primary amide. So the NH should be a primary amide. Therefore, the NMR should show a broad peak around 1-2 ppm. But here it's at 4.0 ppm. This is a problem. However, maybe the data is misinterpreted. Let me check the NMR data again.

Alternatively, perhaps the broad singlet at 4.0 ppm (2H) is not the NH but a different proton. But the molecular formula has NO2 (nitrogen), so the only N is in the amide. Therefore, the NH must be part of the amide. Therefore, the NMR should have the NH at 1-2 ppm. But the data shows it at 4.0 ppm. Therefore, option D is incorrect. 

Wait, perhaps the structure is not a formamide but a different amide. Let me check the options again. Option D is N-(4-ethoxyphenyl)formamide. So the structure is HCONH-Ph-OCH2CH3. The NH is part of the amide. Therefore, the NMR should have the NH around 1-2 ppm. However, the given data shows the NH at 4.0 ppm. This discrepancy suggests that option D is incorrect. 

But then, none of the options match the NMR data except perhaps none. But the problem states that the correct answer is among the options. Therefore, perhaps I made a mistake in interpreting the NMR. Let me think again. The triplet at 1.20 ppm (3H) is ethoxy CH3. The quartet at 4.5 ppm (2H) is ethoxy OCH2. The doublets at 7.0 and 8.0 ppm (each 2H) are the aromatic protons. The broad singlet at 4.0 ppm (2H) is the NH. But if the NH is part of an amide, it should be at a lower ppm. However, maybe the amide is part of a different environment. Alternatively, perhaps the NH is part of a different group. Wait, maybe the compound is not an amide but an amine. Let's check the options again.

Wait, the options are:

A. ethyl 4-aminobenzoate

B. 4-aminophenyl propionate

C. 3-ethoxybenzamide

D. N-(4-ethoxyphenyl)formamide

All of these have either an ester, amine, or amide group. The NMR shows an NH, so it must be an amine or amide. The IR shows a carbonyl, which rules out amines (as they don't have a carbonyl). Therefore, it's either an amide or an ester. The NMR has an NH group, so it's an amide. Therefore, the structure must be an amide. Therefore, option D is the likely answer. But the NMR discrepancy remains. 

Alternatively, perhaps the NH is in a different environment, such as being part of a different group. Wait, but in formamide, the NH is part of the amide. Alternatively, maybe the NH is part of a different functional group. But the molecular formula doesn't match. 

Wait, maybe the compound is ethyl 4-aminobenzoate with an ethoxy group. Wait, but that's not an option. Let me check the molecular formula again for option D. D is N-(4-ethoxyphenyl)formamide. Structure: Ph-OCH2CH3 (ethoxy) attached to the benzene ring, and NH2 connected to the formamide. Wait, no, the structure is HCONH-Ph-OCH2CH3. So molecular formula C9H11NO2. Correct. The IR shows 1720 cm⁻¹ (amide carbonyl). The NMR shows triplet (CH3), quartet (OCH2), and NH (4.0 ppm). But amide NH is usually around 1-2 ppm. Therefore, this is a contradiction. 

Wait, unless the NH is not part of the amide. But option D is formamide, so it must have an amide. Therefore, perhaps the answer is D, and the NMR data is slightly off. Alternatively, maybe the NH is in a different position. Let me check the integration. The NMR has 3H (triplet), 2H (quartet), 2H (doublets), 2H (doublets). That's 3+2+2+2 =9 H. But the molecular formula is C9H11NO2, which has 11 H. Therefore, the remaining H must be 2 H unaccounted for. Wait, but the NMR data provided only accounts for 9 H. Therefore, there's a mistake here. Wait, the problem states the NMR data is {triplet 1.20 ppm (3H); quartet 4.5 ppm (2H); doublets 7.0 ppm (2H), 8.0 ppm (2H)}. So total H: 3+2+2+2=9 H. But the molecular formula is C9H11NO2, which has 11 H. Therefore, there are 2 H missing. Wait, but perhaps the data is incomplete. However, the problem states that the data is provided, so perhaps the 2 H at 7.0 and 8.0 ppm are the aromatic protons, and the remaining 2 H are somewhere else. Wait, the aromatic region in the NMR is 7.0 and 8.0 ppm, each integrating to 2H. That's four aromatic protons. But for a benzene ring with substituents, there should be four aromatic protons if two substituents are present. For example, if the ring has two substituents (ethoxy and NH group), the remaining four protons would be split into two doublets, each integrating to 2H. That makes sense. So the aromatic region is accounted for. The remaining H in the molecular formula are 11-9=2 H. But the NMR doesn't account for them. Therefore, perhaps the data is incomplete, or there's a mistake in the problem. Alternatively, maybe the triplet and quartet are not the ethoxy groups. Wait, the triplet at 1.20 ppm (3H) is likely the CH3 of ethoxy, and the quartet at 4.5 ppm (2H) is the OCH2 of ethoxy. Therefore, the ethoxy groups contribute 5 H. The aromatic contributes 4 H. The remaining 2 H must be the NH protons. But in the NMR data, the NH is a broad singlet at 4.0 ppm (2H). Therefore, the data accounts for all 11 H. So that's confusing. Wait, 3 (CH3) + 2 (OCH2) + 4 (aromatic) + 2 (NH) =11 H. But the NMR data only accounts for 3+2+4=9 H. Therefore, the NH protons are missing from the data. But the problem states that the data includes all signals. Therefore, perhaps the NH is split into two doublets, each integrating to 1H. But the problem states the NH is a broad singlet at 4.0 ppm (2H). Therefore, this is a contradiction. 

Given all this confusion, I think the correct answer is option D, even though there's a discrepancy in the NMR data. Alternatively, perhaps I made a mistake in interpreting the NMR. Let me check once more. The triplet at 1.20 ppm (3H) is CH3 of ethoxy. The quartet at 4.5 ppm (2H) is OCH2. The doublets at 7.0 and 8.0 ppm (each 2H) are aromatic. The broad singlet at 4.0 ppm (2H) is NH. But in the molecular formula, there's only one NH. Therefore, the NMR should have only 2 H for NH. But the molecular formula is C9H11NO2, which has 11 H. The NMR data accounts for 3+2+4+2=11 H. Therefore, the NH is at 4.0 ppm (2H). But in the structure of option D, the NH is part of the amide and should be around 1-2 ppm. Therefore, the NMR data is inconsistent with the structure. 

Given this contradiction, but the fact that the molecular formula and IR match option D, I think the answer is D. Maybe the NH is part of a different group or there's a mistake in the NMR data. Alternatively, perhaps the NH is part of a secondary amide, which can shift upfield. But typically, secondary amides have lower pKa and may have NH signals around 3-4 ppm. However, primary amides are around 1-2 ppm. 

Alternatively, perhaps the NH is part of an amine group, but that would require the structure to have a primary amine, which option D does not. Therefore, I think the answer is D, but there's a discrepancy in the NMR. However, the problem states that the correct answer is among the options, so I'll go with D.
</think>