What Would Be an Accurate Prediction for the Social Brain

What would be an accurate prediction for the social brain hypothesis?

A) The part of the brain that is stimulated by pleasure-enhancing drugs is equally stimulated by time spent with other people.
B) Human beings were not capable of complex social behavior prior to the evolutionary development of certain brain structures.
C) Antagonistic neurotransmitter release is heightened when we are around other people and suppressed when we are alone.
D) A species of gorillas where the members form a social community should have bigger brains than other gorillas whose members live independently of each other.