A、A druggist’s suggestion. B、An article. C、An advertisement. D、A sales clerk’s comment. B从“I saw that article，too．”可知是一篇文章引起两个人的

W: I just read a curious fact. Did you know that people who spend less than ten minutes in a drugstore are five times more likely to make a purchase than those who spend half an hour there?
M: I saw that article, too. But think, if someone runs into a drugstore for ten minutes, it’s usually to make a specific purchase.
W: And someone who spends more time there maybe just looking.
M: Exactly. Haven’t you ever gone into a store thinking that you’d buy something, and then talk yourself out of it?
W: Yes, I have. Especially when I thought I could get it for less elsewhere, or I really didn’t need it after all.
M: Exactly. But if you run in to buy something specific and have very little time, you pick it up, pay for it immediately and then leave.
W: That’s true. Maybe we should learn a lesson from that. Take your time and you’ll spend less money.
M: I doubt if that would be true in all stores, though. In a department store, for instance, you may see a sweater or something you never intended to buy and buy it because you have time to look around.
Questions 16-20 are based on the conversation you have just heard.
16. What prompted the conversation?
17. What is the main topic of the conversation?
18. What fact have the man and woman learned about the drugstores?
19. What does the man say about people who shop quickly?
20. Which of the following statements is true according to the passage?