Which of the Following Has Been Demonstrated About Punitive Sentiments

Which of the following has been demonstrated about punitive sentiments?

A) Observing an unfair game player receiving physical pain activates the brain's reward centers.
B) People who do the punishing and remain anonymous to the person being punished tend to punish cooperators more often.
C) The reward centers in women's brains tend to show higher activation levels in response to witnessing punishment than the reward centers in men's brains.
D) Younger men tend to punish female non-cooperators more than older men.