装配图的作用及内容是什么？

The recent dramatic increase in commuter airline crashes is caused in large part by pilot inexperience. As a major growth industry, the commuter airlines have recently had a great increase in the demand for experienced pilots. It is impossible to define and assess pilot experience, however. For example, someone with 1,000 hours of flight experience as an instructor in Arizona, where the weather is good, cannot be compared to someone with 1,000 hours’ experience as a night cargo pilot in the stormy northeastern United States.
The author’s conclusion that the dramatic increase in commuter airline crashes is caused by pilot inexperience is most weakened by the fact that the author has

A．argued that it is impossible to measure "pilot experience. "

B．used an example that does not relate logically to the point being illustrated.

C．provided only a partial explanation for the increase in commuter airline crashes.

D．made an unfair comparison between experience as a flight instructor and experience as a night cargo pilot.

E．(E) not specified how much of the recent increase in commuter airline crashes is due to pilot inexperience.