Thanks for the question! We’re dealing here with a main point question. As such, we should go through the passage and try to get a broad sense of what it’s talking about, which is (in big picture terms) a discussion of clinical vs. theoretical equipoise. (A) is wrong because first, it’s not a claim that’s made in the passage. The author doesn’t state or imply that the overly strict conception of theoretical equipoise jeopardizes the ethical requirement of prescribing the best available treatment. It’s also wrong because even if this were true, it wouldn’t be the main point of the passage, which seems to be introducing and supporting a notion of “clinical equipoise.†Hope this helps! Feel free to ask any other questions that you might have.