The low-pass Sallen-Key filter, of course! Whats the matter? Youre not laughing at my answer. What Im doing here is asking you to some research on Sallen-Key filters to confirm your qualitative analysis. And yes, I do expect you to be able to figure out which of the two filters is low-pass based on your knowledge of capacitors and op-amps, not just look up the answer in an op-amp reference book!