A、At a music store. B、At the post office. C、On the Internet. D、At a German party. C细节题。Pete说I met this really nice woman through

Pete: Hey Markus. I have a question I’d like to ask you.
Markus: Yes. Go ahead.
Pete: Well, I’m thinking about going to Germany this summer, and I need some advice. You’re the best person I know to answer my questions since you’re German.
Markus: Thank you. What do you want to know?
Pete: Well, don’t laugh, but I met this really nice woman through an online music mailing list, you know, a discussion group on the Internet. I need some advice. You see, Claudia,...
Markus: Okay. So it’s Claudia, oh?
Pete: Yeah, yeah. See, she invited me to spend two weeks in Germany. And well, I told her I had studied a little bit about the country and language, and she’s kind of expecting that I know more than I really do.
Markus: Hum. You’re really in hot water now!
Pete: Yeah. I think so.
Markus: Well, what do you want to know?
Pete: Well, she’s planning on introducing me to her parents.
Markus: Hey. Sounds kind of serious.
Pete: It isn’t, at least I think it isn’t. Anyway, what should you do when you greet someone for the first time in Germany?
Markus: Well, it depends upon your relationship with the person. Now, speaking of your girlfriend, Claudia.....
Pete: Hey, I didn’t say she was my girlfriend.
Markus: Ah, okay, okay. Now if you’re meeting someone formally for the first time, like Claudia’s parents, you should make sure you arrive on time.
Pete: Okay, so arrive on time. Uh, what about common greetings?
Markus: Well, Germans often shake hands, and they use the person’s family name, unless they’re really close friends.
Pete: Okay, what about with Claudia? I’m not sure what I should do in her case.
Markus: Ah. You can call her Claudia, shake hands, and why don’t you take her some flowers?
Pete: Oh, how do you say "Nice to meet you" anyway?
Markus: Oh, "Ich freue mich, Sie kennenzulernen. "
Pete: "Ich freu me senselen... ? "
Markus: Uhhh. Not exactly. "Ich freue mich, Sie kennenzulernen".
Markus: Humm. Honestly, I think you need to take a crash course in German before you leave. Claudia might think you’re speaking Chinese or something if you don’t.
Questions:
19. Where did he meet Claudia?
20. What is one thing Markus does NOT say about greeting Claudia?
21. What does Markus finally advice Pete to do?