We have no reason to think evidence of the butchering of animals by early humans could suggest that cooking might have affected human evolution. Butchering of animals can occur to prepare them for raw consumption, so we can’t interpret (A) as evidence that cooking has been around for a long time.

This strengthens the author’s claim by showing that the assumption in the view the author criticizes is wrong. That view assumes that in order for a practice to affect human evolution, it can’t be a recent practice in human history. But (B) shows that a practice that has been around for fewer than 5,000 years (drinking milk), which is still relatively recent when you consider the scale of early human history, did affect human evolution.

We have no reason to think the correspondence between fire use and climatic changes that produced the ice ages suggests anything about the timeline required for cooking to affect human evolution.

(D) may establish that early humans ate more plants. But we have no reason to think that a diet higher in plants has anything to do with the timeline required for cooking to affect human evolution.

(E) establishes that there have been changes in human evolution in the past 100,000 years, because we know from the passage that tooth/jaw began decreasing about 100,000 years ago. But we have no idea whether the changes in brain volume are related to any recent human practice. So (E) doesn’t suggest anything about the timeline required for cooking to affect human evolution.