My thought process for Q 20 -
It's a broad question, so I'm just going to dive into the answers.
A) The passage doesn't discuss clinical trials in detail, so I don't know if they are conducted to meet the appropriate ethical standards or not.
B) This one was really tempting -
We know that by adhering to the standard of theoretical equipoise, few clinical trials would take place. With a more reasonable ethical standard, would more clinical trials take place? Intuitively, I want to say yes, but this isn't supported by the passage. The author doesn't discuss that more would take place.
C) Yep! Line 20-21 "an ideal hardly attainable in practice" in reference to theoretical equipose.
D) We don't know at all if they think these ethical requirements are adequate or not. We know that the author thinks its too strict, but is the author representative? Who knows?
E) Most comparative clinical trials? Although this is discussed in the third paragraph, it was not mentioned as "most comparative clinical trials."
C it is!