Why did the man go to see the doctor?

Listen to the conversation， mark each question as A， B， C or D according to what you hear.
W: Hello， Jim. I haven’t seen you for a while. What seems to be the problem?
M: Actually I’m a little embarrassed about coming here. I feel alright now. But you know how many viruses are going around. Anyway every year around the holidays， like clockwork， I come down with something.
W: So you are interested in prevention. What symptoms do you usually get?
M: You know， cough， fever， running nose， my head and bones ache， chills even. I’m usually miserable for a week and it ends up ruining my holidays.
W: Sounds like a typical flu to me. As you said， lots of people have it. Influenza often strikes when people are overtired， stressed out and not eating enough nutritious food. And also you increase your exposure to a virus when you’re in big crowds where lots of people are coughing and sneezing.
M: I certainly spend a lot of time in department stores around the holidays buying gifts for people.
W: Yes. And so you increase your exposure to airborne viruses just when your body’s resistance is already low from all the running around you do.
M: So what can I do to ward off the flu?
W: Actually it’s fairly simple. Get a lot of rest， eat well. That way your immune system will be boosted. And you will be more able to fight off illness.
M: All these things make sense. But one more question. Aren’t I bound to get sick anyway if there’s an outbreak in the dorm?
W: Oh， you didn’t mention you lived in a dormitory. In that case， I’d also suggest you get immunized. The available vaccine prevents the three main types of influenza. Why don’t you go to the university health center? The shots are free there.
M: I’ll do it right away. It will be nice to feel well during the holidays for once.