【正确答案】 D

【答案解析】[听力原文]
W: Good evening. Welcome to our program, Jack.
M: Thanks.
W: How long have you been a police officer?
M: Thirty years. I've done different types of assignments on the police force, from patrol to undercover work to detective work, and I'm supervising investigations now.
W: Is being a police officer stressful?
M: Yes, definitely. But it depends on your assignment.
W: Which assignment is most stressful in your opinion?
M: Patrol.
W: Oh, really? But why?
M: Because the biggest part of the stress is the fear factor-the fear of unknown.
W: What do you mean by "the fear of unknown"?
M: Well, in patrol work, you don't know from moment to moment who you are talking to or what their reaction is going to be to justify your presence. For example, if a patrol officer stops someone for a traffic violation, the driver may try to escape or even back over the officer. So, that's really a very dangerous job and full of risks.
W: I see. It's a risky job and you have to protect yourself all the time.
M: Thus all police officers are taught from the very beginning to be aware of their surroundings. People back over them, shoot them, or jump out at the-all kinds of things. That's full of pressure.
W: I see. Well, Jack, thank you for coming to our program and share your work with us.
M: You're welcome.

What's the relationship between the two speakers?