Which Adult's Remark Helps to Promote Prosocial Behavior

Which adult's remark helps to promote prosocial behavior?

A) A father says, "Because you teased your little brother, you are grounded."
B) A mother says, "You are such a kind person to shovel the snow off Mrs. O'Connell's driveway!"
C) An aunt says, "I'll pay you if you are nice to your baby cousin."
D) A teacher says, "You are such a bad boy for acting mean in class!"