A、Wearing arm weights while you are swimming. B、Jogging vigorously in one place for a long time. C、Using bicycles that require y

W: Exercise, exercise, exercise! We hear so much about it these days that even the experts can’t agree on which exercises are best. Now some doctors are strongly encouraging arm exercises.
M: Arm exercises? I’ve never heard of that. Is that because our arms are too fat or flabby?
W: Actually, that’s not the main reason. They say that arm exercises are an ideal way to become physically fit.
M: But don’t arm exercises raise your blood pressure? Seems I’ve read an article about that before. So, that’s risky.
W: Not really. That they do, but the article I read mentioned several ways that can compensate for that.
M: Really? How?
W: By adding leg exercise so the arms don’t do all the work. Arm exercises alone aren’t enough to increase metabolism before fatigue sets in. The more of a body that involves in the exercise the better.
M: And in turn, I’m sure that there is a great chance of losing weight, right?
W: Sounds right to me.
M: So, what exercises do the experts recommend?
W: They mentioned quite a few. But some of the more popular ones are cycling with special bicycles that make you use both your arms and legs, and walking vigorously while wearing arm weights.
M: Sounds great. I must try that. You know, I like to walk a lot.
Questions 13 to 15 are based on the conversation you have just heard.
13. According to the conversation, what is one problem with arm exercises?
14. According to the conversation, what are the experts now recommending?
15. What form of exercise does the woman mention?