A)The woman has trouble getting along with the professor.
B)The woman regrets having taken up much of the professor's time.
C)The woman knows the professor has been busy.
D)The woman knows the professor has run into trouble.
原文：
M: Prof. Kennedy has been very busy this semester. As far as I know, he works until
midnight every day.
W: I would't have troubled him so much if I had known be was so busy.
Q: What do we learn from the conversation?