Sentence Correction

By 1960, the pilot Rolph held sixteen official international speed records, and he earned them at a time when aviation was still so new for many of the planes he flew to be of dangerously experimental design.

(A) and he earned them at a time when aviation was still so new for many of the planes he flew to be

(B) earning them at a time that aviation was still so new for many of the planes he flew were

(C) earning these at a time where aviation was still so new that many of the planes he flew were

(D) earned at a time in which aviation was still so new such that many of the planes he flew were

(E) earned at a time when aviation was still so new that many of the planes he flew were



OA E

Source: GMAT Prep