求证way的用法

这道题答案没什么问题，我想问way of doing和way to do 在gmat是不是都允许？谢谢！

7. Everyone participating in the early sociological study committed a crucial methodological error by failing to fully consider alternative ways of classifying their data.
(A) by failing to fully consider alternative ways of classifying their
(B) by failing fully to consider alternative ways of classifying their
(C) they failed to consider alternative ways to classify their
(D) by not fully considering alternative ways to classify the
(E) by not considering fully alternative ways of classifying his or her