单项选择题

W: Hi, Sam, would you like to go swimming this afternoon
M: I wish I could, but I have to spend the rest of the day in the library. I have a ten-page paper due tomorrow.
W: Oh, is that for Professor Lowal’ s class
M: Yes.
W: That’ s hard. How was it going so far
M: Not very well. And I also have to study a lot for math and history. I don’ t know how I’ m going to do at all.
W: You know, Sam. I’ ve been doing well in math, so I’ ll be happy to help you.
M: Ah, that would be great, Jenny.
W: If you like we can start after we come back from swimming.
M: OK, I’ ll see you in front of the library.
W: Good luck with your paper.

Why can’ t Sam go with Jenny()

A. He must attend Professor Lowal’ s class.
B. He has to finish a paper.
C. He’ s going to a conference.
D. He has to take a math test.