单项选择题

Speaker A: Excuse me, Professor Smith, can you spare me a few minutes There’s something I’d like to speak to you about. I won’t keep you long.
Speaker B:_________

A.Of course not. Haven’t you seen have been pretty busy now
B.Well, I’m afraid we have to find some other time. I’m fully occupied now.
C.No. I’ll have an important meeting to attend this evening.
D.Not possible, as I don’t know how long you will keep me.