[求助]LSAT-1-1-16

16. Investigators concluded that human failure was not resposible for the fatalairplane crash last August, and since that time new and more stringent rules for identifying and reporting mechanical problems have been in effect. That accounts for the fact that reports of airplane mechanical problems have increased in frequency by 50 percent since last August.

Which one of the following is an assumption underlying the argument in the passage?

A. Airplane travel is still relatively rare, despite the increase in reported mechanical problems.

B. Mechanical problems in airplanes have increased dramatically since last August.

C. Mechanical problems in airplanes have not increased by 50 percent since last August.

D. Airlines are less reluctant to report mechanical problems than they previously were.

E. Mechanical problems in airplanes have become easier to detect since last August.

答案是C, 我是一点都不明白啊, 请各位大虾帮忙啊.

conclusion是他的新规定起作用了，因为report for mechanical problem增加了1／2。如果我真正的mechanical problem从八月的时候是增加了1／2，那不管新的规定，report都应增加1／2.。所以文章assume mechanical problem没有增加到1／2，但新的规定使report更严格了，这样report的数量也更多了。