大全 test3 problem 18

 Teresa: Manned spaceflight does not have a future, since it cannot compete economically with other means of accomplishing the objectives of spaceflight.

Edward: No mode of human transportation has a better record of reliability: two accidents in 25 years. Thus manned spaceflight definitely has apositive future.

Which of the following is the best logical evaluation of Edward's argument as a response to Teresa's argument?

C. It raised a consideration that outweighs the argument Tersa makes

D. It doesn't meet Teresa's point because it assumes that there is no serious impediment to transporting people into space, but this was the issue raised by Teresa

The correct answer is D. But I don't know why C is wrong, since Edward indeed raised the concern of safty. And for D, why does it state that Edward's argument assumes there is no serious impediment to transporting people into space? I think the safty issue is mentioned.

Thanks