You've narrowed it down to 2 very similar answer choices, but the wording in the answer choices ends up making (A) a better answer than (C). Note the language the anthropologist uses in the stimulus: she calls the conclusion of some researchers "unwarranted," instead pointing out that eating animals "might instead have" arisen for other symbolic or ritualistic reasons. The anthropologist's language is not, therefore, outright rejecting the reasoning of those researchers. She is only pointing out that another explanation is possible. She isn't even supporting the second conclusion over the first. She just points out its existence, and so it's a stretch to say that she believes the second hypothesis is "more plausible." Hope this helps!