You are an expert human evaluator specializing in text summarization.
Your task is to meticulously compare two summaries, "Summary A" and "Summary B," generated from the same "Original Document."
Your goal is to determine which summary is of higher quality overall.

Please consider the following criteria in your evaluation:

1.  **Accuracy & Faithfulness:**
    *   Does the summary accurately represent the main points of the original document?
    *   Does it avoid introducing new information or misinterpreting facts from the document (hallucinations)?
2.  **Coverage & Comprehensiveness:**
    *   Does the summary cover the most important information and key takeaways from the original document?
    *   Are there any critical omissions of essential information?
3.  **Conciseness & Succinctness:**
    *   Is the summary brief and to the point, avoiding unnecessary jargon, redundancy, or overly verbose phrasing, while still capturing essential information?
    *   Is it significantly shorter than the original document, as a good summary should be?
4.  **Clarity & Readability:**
    *   Is the summary well-written, grammatically correct, easy to understand, and fluent?
    *   Is the language clear and precise?
5.  **Coherence:**
    *   Do the sentences in the summary flow logically? Does it make sense as a standalone piece of text?
    *   Is there a logical structure to the summary?

**Input:**

**Original Document:**
```
{original_document}
```

**Summary A:**
```
{summary_A}
```

**Summary B:**
```
{summary_B}
```

**Instructions for your response:**

1.  **Reasoning:**
    *   First, briefly state your understanding of the main purpose or key points of the **Original Document**.
    *   Then, provide a step-by-step comparative analysis of Summary A and Summary B based on the criteria listed above (Accuracy, Coverage, Conciseness, Clarity, Coherence).
    *   For each criterion, explicitly compare A and B. For instance, "Regarding Accuracy, Summary A does X well, while Summary B struggles with Y..."
    *   Point out specific strengths and weaknesses of each summary. You can reference parts of the summaries or the original document if helpful (e.g., "Summary A correctly captures the detail about X from paragraph 2 of the document, whereas Summary B omits this.").

2.  **Overall Decision:**
    *   After your detailed reasoning, clearly state which summary you believe is better overall and why, making a holistic judgment. If they are of very comparable quality, or if one excels in some areas while the other excels in others making a clear choice difficult, you can indicate that.

**Output Format:**

First, provide your detailed **Reasoning** as described above.
Then, on a new line, write "**Overall Decision:**" followed by your overall assessment.
Finally, on a separate, new line, output *only* one letter:
    *   'A' if Summary A is better.
    *   'B' if Summary B is better.
    *   'C' if both summaries are of very similar quality (a tie), or if one is not definitively superior to the other across the most important criteria.

**Output:**