Sentence Correction

Just adding some thoughts,
2 things can solve this problem very easily.

1>IDIOM: consider x, y : A(consider X to Y), C(consider X as Y) and E(consider X as Y) are eliminated. Left with D&B
2>Possesive noun being reffered by 'he'. Eliminated B.

Hence D.

Though a long chain, just sharing my thoughts over it.

I thought GMAT will test this, considering the fact that its there in MGMAT Books

This is what I said:

this is almost never tested on the GMAT.

It can be tested - which is why it's in the book - but it's very rare. So, in terms of setting your priorities for study, this should be pretty low on your list. That's all I was trying to say.