A、Three packages. B、Five packages. C、Seven packages. D、Nine packages. C对话中，提到买多少热狗时，女士提到了很喜欢吃热狗的Jim，最终与男士达成一致，决定买七包热狗。故本题答案为C。

W: Dave. (19)I’m going to the supermarket to pick up food and drink for Saturday’s picnic later. Any suggestions?
M: Well, (19)everyone has been talking about having a barbecue down by the river, so why don’t you pick up some hamburger and hot dogs?
W: Okay, but how much hamburger meat are we going to need? And hot dogs too?
M: Uh, I don’t know. How about three pounds of hamburger and a couple packages of hot dogs?
W: Oh, that’s not going to be enough. Do you remember the last picnic we went on? Your roommate, Jim, ate about ten hamburgers by himself!
M: You’re right. (20)Let’s buy nine pounds of hamburger meat and seven packages of hot dogs then.
W: And you’d better pick up some chicken for those who don’t like hamburgers or hot dogs.
M: Okay. How about five or six bags of potato chips?
W: Better make that eight or so.
M: Alright. Oh, and we’re going to need some hamburger and hot dog buns. How about five packages a piece? I think that sounds about right.
W: Yeah, you’d better pick up some mustard, catch up, and mayonnaise, too.
M: Okay. What else? Uh, we’re going to need some soft drinks. How about ten of those big 2-liter bottles?
W: Sounds tine, but be sure to buy a variety of drinks.
M: Okay. And what about dessert?
W: Well, maybe we could ask Kathy to make a few cherry pies as she did last time.
M: Well, I wouldn’t mind that, but you know, she’s been very busy working two jobs, so I’d hate to ask her. (21)OK, to be honest, I have broken up with her last week, and we haven’t talked since then.