The word "discrepancy" (Para. 3) most probably means ______.

A．It requires formal training.
B．It is often enjoyed by those with strong analytical ability.
C．It is disliked by blacks.
D．It is more difficult to learn than classical music.

A．Are musical ability and mathematical ability connected
B．Why have blacks been greatly over represented in the development of American popular music
C．What kinds of music require formal training
D．What are the contributions made by black musicians