~~请问大家大全section D 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（D）

(E) by not considering fully alternative ways of classifying his or her

这一题答案选D，但是A为什么不行了，另外way的用法是不是a way to do和a way of doing 都可以呢？

谢谢大家

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

Everyone is singular, it can not be matched with their