It would be better to end the sentence with "to do so" to explain the complete action.

B)has devoted his subsequent career to do that.. no referent
C)devoted his subsequent career to such an end ....such means, like what? dont know
D)has devoted his subsequent career for that ...no referent
E)devoted his subsequent career to that end

to that end is a correct phrase and next best answer

OA is E

A- it is ambiguous because it refers to phrase "to find site of ancient troy"

B- has indicates that the search is still on..INCORRECT

C- Incorrect Idiom such..as

D- Same as B

E seems to be the best answer.

OA please!

A) Devoted his subsequent career to do it.
B)has devoted his subsequent career to do that
C)devoted his subsequent career to such an end
D)has devoted his subsequent career for that
E)devoted his subsequent career to that end

Like schumi said, At A, B and D you can't figure out what those pronouns are reffering too.

C. Such reffers too?

So E is the answer!