I almost chose C over D because if many doctors are prescribing it, that may mean that the medical community still endorses its use or might see the side-effects as less harmful than the benefits obtained from taking the drug. Would I be reading too much into it?

I was stuck between A and C. I chose A over C because I think the assumption that self reporting can be inaccurate is more reasonable than the assumption that researchers need accurate self-reports to be effective. For example, perhaps they can conduct rigorous psychological work on a self-report that is inaccurate and identify patterns of fabrications and learn about the subject from them. I'm not saying this is the case, but it was a possibility that popped into my mind and I thought A bridged the gap created by that possibility, which seems to be less reasonably inferred away and more disruptive to the argument than the gap filled by C.

I answered D because it is not explicitly stated that one must understand the language to "witness" the beauty of poetry. I understand that the author implies that one must understand the language to appreciate the beauty of its poetry, but it feels like a large assumption. Theoretically, one could "witness" the beauty of poetry, such as Chinese calligraphy, without understanding the language. Am I wrong/missing something? Thanks for the help!