Once again, I'm writing explanations to help with my own review.
Correct answer: (C)
A lesson to myself: to handle these "role in the argument" questions in both RC and LR, it is beneficial to get used to some very abstract characterizing phrases.
(A) Although the author presents a counter-thesis to that of the multiverse theorists, in the final paragraphs he nonetheless claims that his research does not call the concept of the multiverse into question (line 49). Hence, he does not see the multiverse model as inadequate.
(B) This one was a contender for me on the timed test. I think it is natural for researchers to raise objections within their own argument only as further questions to explore in order to further extend and consolidate their thesis. Not in this case, though. The final paragraphs turns out to concede somewhat to the argument that earlier paragraphs have provided evidence against.
(C) CORRECT. This is a safe, general characterization of the function of the final paragraph. The wording is much safer than (B).
(D) Thankfully I had settled with (C) in my mind at this point, so I wasn't tempted by (D). The author does raises two points that support the multiverse model, but not as counterarguments, rather in order to concede to his "opponents."
(E) This answer choice in sort of similar to (B), but is much easier to eliminate, since there is no mention of any sort of experimentation.