A、It’s not safe for them. B、Everyone respect them. C、They are easier to find partners. D、They only hitchhike in Britain. A女士问男士，

W: Welcome to Backpack Travel! I’m your host, Stacy Goodwin. Today our program is about hitchhiking. We have Dennis Hornyak here to share his hitchhiking experience. Thank you for joining us, Mr. Hornyak
M: Call me Dennis, please.
W: Okay, Dennis. Do you hitchhike to save money or do you hitchhike for some other reason?
M: I haven’t got any money to save! I’m a student. I hitchhike in order to travel and, of course, to meet people.
W: Is it easy to get a lift? Do people stop or do you have to wait a very long time?
M: It depends where you are, what time it is and how many people are with you and whether they are men or women!
W: Isn’t it dangerous for a woman to hitchhike by herself?
M:[20]Yes. On the other hand a lot of things are dangerous. It is very dangerous to travel in a car. And, in any case, most people in Britain will be respectful of her right to travel as she wants.
W: And is it faster for you if you travel with a woman?
M: Yes, it’s certainly faster.
W: How do you stop the cars?
M: In Britain you just hold out your hand, usually you put your thumb upwards. Actually, the best system is to have a sign and make the letters big.
W: Any more tips?
M: Well, you learn all kinds of things when you do it. The main advice is, try it! You’ll meet a lot of different people. And you’ll learn a lot about the country.
19. For what purpose did the man hitchhike?
20. What do we learn about women’s hitchhiking?
21. What is the best system to stop cars in Britain according to the man?