A、The man. B、The girl herself. C、Her sister. D、Not mentioned. A

M: You look happy. Did you sell lots of things at the store today?
W: No. I bought something. It was a great deal.
M: So what is it?
W: A laptop computer.
M: Really? That’s great. They are really convenient. You can take them anywhere.
W: You are right. That’s what I thought. I can use the computer at home and at my store.
M: What will you use it for at the store?
W: To keep track of all the things in the store. How much I sell them for and which article sells best, and what are the things in sufficient stock.
M: That’s a good idea. But I didn’t think you knew how to use a computer.
W: I have to say I don’t.
M: Then why did you buy one?
W: I’ve heard so much about computers. And I’ve heard you can find so many interesting things online. I was walking past the computer store downtown. I saw they had computers on sale.
M: So you went into the store to ask a few questions.
W: That’s right. And I met a nice, young salesman. He showed me lots of things a computer can do. I just had to buy one.
M: So now who is going to teach you to use it?
W: You are.