- Tue Sep 24, 2019 12:55 pm
Just a quick note before I answer your question directly: most main points are located at either the end of the first paragraph, the last paragraph, or as a synthesis of both. Here, we have the latter, where the close relative hypothesis serves as a causal explanation for some instances of helping close kin reproduce, but not for all. (A) represents this synthesis of the information in the first and last paragraphs perfectly.
(B) fails in that it doesn't deal at all with the actual issue in the passage, which is whether the theory actually explains animal reproductive behaviors or not. How varied the mechanisms that enable species to recognize their close kin only serves as background information as to the fundamental question of why these mechanisms exist and whether this particular hypothesis answers that question.
Hope this clears things up!