I am not sure whether there is 'had been' in any of the choices.

But, the first clause should modify 'the employee'.

Hence A and B are wrong.

since 'believed' happened after 'moral victory is won', the 'won' should be in past perfect tense [had won]

D) to have been won - awkward
E) was won - not appropriate

C) correct [modifier is correct, had won says that won happened before believed]

makes sense?

That makes sense. Thanks

I could not find 'had been' in the answer choice either so thought i ask the question.

option A.
First of all, we must make sure our answer is in active form and not in passive form. So we had to choose an answer in the active form is which option is not one.Therefore, this option is wrong.

Option B.
This option suffers the same fate as option A above because the option is not constructed in an active form.Therefore, this option is incorrect.

Option C.
what did the employee believe? This is a straight answer and well-constructed sentence, and it follows proper parallelism thus, this is the correct answer.

Option D.
it would be improper for her moral victory to be won rather but won her moral victory instead.
Sentence construction is vital here, thus this option is incorrect.
Option E.
This option suffers the same fate as option D above.