A)He will only be available in the afternoon.
B)It's not his office hour.
C)He doesn't have time.
D)He is too tired after class.
原文：
W: Excuse me, Professor Hill. May I ask you a few questions?
M: Yes, of course. But I'm sorry I have a class at ten. Why don't you come in my
office hours. That is 4 to 5 P.m. Monday, Thursday and Friday.
Q: Why can't professor Hill answer her question noew?