A、When the doctor told him to. B、When his wife told him to. C、When he had to. D、When he felt better. D

M: Doctor Brook, I just don’t know what’s wrong with mc. I always feel tired and rundown. My wife finally persuaded me to visit you to find out what the trouble is.
W: Looking at your case history I see that you had pneumonia four years ago and that you also had a minor operation last year. Did you have any long aftereffects?
M: Well, I don’t remember so...
W: For instance, how long did you stay at home each time?
M: Just a couple of days. But about six months ago I was home for about two weeks with a cold or something.
W: Did you see a doctor at that time or did you just stay home?
M: No, I didn’t see a doctor. The symptoms were ’about the same as this time. When I began ’to feel better, I returned to work.
W: And when did you start feeling so tired again?
M: It must have been about ten days ago. When I came home from work one night there just didn’t seem to be any reason to go back the next day.
W: Well, it sounds as if your problem may be the kind of work you do. The tests I just made don’t show anything really wrong. But I would like to make some further tests in the hospital.
M: That’s fine with me.
W: All right, you can check in tonight and I’ll make the tests tomorrow morning.