Concision Doubt

By 1940, the pilot Jacqueline Cochran held seventeen
official national and international speed records, and
she earned them at a time when aviation was still so
new for many of the planes she flew to be of
dangerously experimental design.
(A) and she earned them at a time when aviation
was still so new for many of the planes she flew
to be
(B) earning them at a time that aviation was still so
new for many of the planes she flew to be
(C) earning these at a time where aviation was still
so new that many of the planes she flew were
(D) earned at a time in which aviation was still so
new such that many of the planes she flew were
(E) earned at a time when aviation was still so new
that many of the planes she flew were


OA IS E. But my doubts is related to option A.
OG mentions that A is wrong for two reasons:
too Wordy.
Wrong Idiom ( "So new X for Y" instead of "So new X that Y").

So my question is can GMAC Test Makers provides any SC questions with two options that are grammatically OK but one is wordier than others?

I mean in option A if we correct idiom issue then A and E differs in terms of concision.I have generally seen there is always some other grammatical errors besides wordiness in two closely related options.

Please clarify on this...