【正确答案】 B

【答案解析】man: Recently, I have done a survey on obesity among children and adolescents. woman： Oh, interesting. What’s the result? man： It shows that about 16 percent of children and adolescents we have interviewed are obese. Among them, the largest increase in obesity rate over the past 5 years occurred among adolescents aged 12 to 17 with the rate increasing from 3% to 9%. woman: Childhood obesity is a serious problem! Some days ago, I learned from another survey that unhealthy weight gain due to poor diet and lack of exercise is responsible for over 300,000 deaths each year. man: Yes, we are all shocked by the conclusion we have made through our survey. But due to some limitations, we cannot get more accurate results. woman： Er. What’s wrong with it? man： Well, we've planned to interview about 1,000 children at first, but only about three quarters of them answered our calls. So the number of children involved is not large enough.

【正确答案】 B