dialogue: W: David. have you ever placed an ad in the Campus Daily? M: Yes. I once did that to sell my bike I no longer needed. W: When was that? M: Last May. I think. Why do you ask? W: I'm thinking of selling my old book since I am going to graduate. M: Are they in good condition? W: Pretty good. M: Well. you can call Berne Li. He is the head of the advertising department of the paper. W: Do you know what rates they charge? M: Last May it was 10 yuan for the first 30 words and 50 fen for each word added. W: 10 yuan for the first 30 words. That is not too bad. M: Yeah. it's reasonable. W: Do they charge extra for pictures? M: No. that's free. But they do charge you more if you Want to put in a bow or something. W: I see. Thanks. That's very helpful. M: It's a pleasure.
question: What are the speakers talking about?
choice: Selling bike. Selling books. Ad in Campus Daily.
answer: Ad in Campus Daily.