61. Investigators concluded that human failure was not responsible for the fatal airplane 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 safe, 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 我选的是E.事故不是因为人为的错误引起的，那应该是因为机械的问题吧,怎么c反而说机械问题没那么多呢? 新的制度生效了,问题应该更容易被发现才对吧??? 哪位牛人赐教一下,谢啦. | 
