笔记一题

102. Compared to those who do not, running three days a week saves an average of 14.1 percent on health-care costs each year in the United States.

A. Compared to those who do not, running three days a week saves

B. Compared with nonrunners, people who run three days a week save
            

C. Compared to not running, those running for three days a week save

D. When compared with those who do not, people running three days a week save

E. When compared to nonrunners, running three days a week saves

D为什么不对呢？答案给的是B。多谢不吝赐教！