听力原文：W: Excuse me, do you know how it works？
M: Yes. Put the washing inside, shut the door, the money goes here. Then when the machine starts, you have to put the soap powder in through here.
W: Is that all？
M: Yes.
W: But is there anything I should do when it works？
M: You don't have to do anything else until the machine stops.
W: Thank you very much.
What can we learn from this conversation？

A. The man knows how to use the machine.
B. The woman knows how to use the machine.
C. They both know how to use the machine.