16. Instead of blaming an airline accident on pilot error, investigators should find out why the error was made by analyzing airplane design, airline management, and pilot-training programs. For only then can changes be made to ensure that the same type of error does not recur and cause another accident.

Which of the following is a presupposition of the argument above?

(A) Pilot error is not a contributing factor in most airline accidents.

(B) Airline companies themselves should be the agents who investigate airline accidents.

(C) Stricter government regulation of airline companies will make air travel significantly safer.

(D) Investigators of airline accidents should contribute to the prevention of future accidents.（D）

(E) Most pilots who make errors in flying will repeat their errors unless they are retrained.

請問各位高手，為什麼不能選A呢?