听力原文：M: Ow ! That hurts !
W: What happened？ Did you cut yourself？
M: Yes. On the edge of this paper. How can such a little cut hurt so much？ I'm not even bleeding, but my finger really hurt.
W: You know, I read something about that. It turns out that a little cut on a finger can hurt a lot more than a big cut somewhere else.
M: Why？ That doesn't make any sense.
W: Actually, it does. There are more nerve endings in your hands than almost anywhere else in the body, and it's the nerve endings that allow you to feel pain.
M: I guess that's tree.
W: Also, a little cut like yours won't damage the nerve endings, just irritate them. If they were damaged, you'd feel less pain, but the wound could be more serious.
M: So I suppose I should be happy my finger hurts so much, right？
W: Right. Now go get yourself a bandage.
M: Why？ You just told me it's not serious.
W: It's not, but it does seem to be bothering you. Putting a bandage over the cut will keep the skin from drying and will help keep the skin together. If the skin stays together, the nerve endings won't be exposed, and the cut will hurt less.
How did the man cut himself？

A. With a knife.
B. On the edge of some metal.
C. On some glass.
D. On a piece of paper.