Why Does Each Answer State the Negation?

Hi Jalen, this is a necessary assumption question, although the phrasing of the question is a bit uncommon.

Hi, can someone please explain this negation and why is E the answer?

The Author rejects the hypothesis that lobsters in traps eat each other because of hunger on the grounds that lobsters in a trap for two months did not eat each other. There is a massive issue here: what if the lobsters never reached the level of hunger in those two months that would be needed for cannabilism. This is why the author must believe E. If the food they were able to get in the trap was enough to stave off hunger, they would have had no reason to eat each other, and thus the authors evidence would not support the conclusion.