PT 66 S2 Q23

As a general rule, the larger a social group of primates,the more time ... ...

Which one of the following, if true, would do most to resolve the apparent discrepancy described above?
(A) Early humans were much more likely to groom themselves than are the members of other primate species.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in June 2012 LSAT (PT66): Logical Reasoning A