This doesn’t capture the author’s hypothesis. Even if you think the fact humans can’t survive on only raw food is a puzzle, since she provides a potential answer to the puzzle, her primary purpose should involve the author’s answer — that humans are biologically adapted to eating cooked food as a result of cooking. Notice that the author also provides some specific aspects of human evolution that she believes limit our ability to eat raw food. This shows that her purpose isn’t mainly to describe a puzzle; it’s to provide answers to the puzzle.

You might think that the view that cooking would not have led to changes in human digestive anatomy is a “common scientific misconception.” This isn’t supported, because the author never suggests that it’s “common” to hold this view. In any case, even if we accept that this is a a common scientific misconception (which is not clear), this is too narrow. (B) ignores the fact that in P2 and P3, the author discusses specific ways in which humans might have adapted biologically and the evidence that shows a potential causal relationship between human evolution and cooking.

(C) asserts that the primary purpose is to explain the meaning of a hypothesis. This doesn’t capture the author’s opinion. She isn’t merely trying to explain what a hypothesis means. She supports a hypothesis and is trying to convince the reader that the hypothesis is plausible.

This best captures the purpose, which is to present her hypothesis that humans biologically adapated to cooked foods as a result of cooking, and to discuss some evidence that might support that hypothesis.

There’s no scientific principle that the author criticizes. Although the author does criticize the view that cooking couldn’t have affected human evolution because it’s too recent, that isn’t a scientific principle.