The author’s argument in the third and fourth paragraphs would be most ... ...

The author’s argument in the third and fourth paragraphs would be most weakened if which one of the following were true?
(A) In most comparative clinical trials, the main purpose is to prove definitively that a treatment considered best by a consensus of relevant experts is in fact superior to the alternative being tested.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in PT72 (Jun 2014): Reading Comprehension