Hi @ctran17, thanks for your question. The stimulus presents two supposedly individually sufficient reasons for not eating meat: (1) one based on health considerations, and (2) one based on an aversion to living at the expense of other conscious creatures.
The supposition that eating meat is essential to good human health is designed to show that perhaps the second reason given is not actually independently sufficient to justify a vegetarian diet. It is NOT used to disprove the claim that a vegetarian diet is healthy.
The key here is to answer the actual question — which asks you to describe the role played in the argument by the supposition that eating meat is essential to good health. In the context of this stimulus, that supposition is not used to disprove the claim that a vegetarian diet is healthy, which is why answer choice (C) is wrong.
Hope this helps! Please let us know if you have any additional questions.
