Regarding Gender Differences in Childrearing Practices, What Has Research Demonstrated

Regarding gender differences in childrearing practices, what has research demonstrated?

A) That most parents try to teach boys compliance early to curb their aggression.
B) That fathers tend to enforce conventional gender roles more than mothers do.
C) That girls are encouraged to play more competitively today than in the past and are rewarded for this behaviour.
D) That boys are encouraged to engage in role-playing games, but are punished for games that seem too feminine.