听力原文：M: Do you happen to have any stamps in your place？
W: Yes, I have some. What stamps do you want？
M: Four fifties and tens
W: I don't think I have that many. But I have an idea, why not use our school's envelopes？ Here you are.
M: What is the difference？ We still need to buy stamps.
W: No, look here, Postage Paid.
M: That's great. You are a big help.
What stamps does the man want？

A. Four fifties.
B. Four tens.
C. Four fifties and tens.