School desegregation has worked well in Buffalo, New York, in part bec

A and C are the only answers that are parallel. B might seem to be parallel, but in fact the because in B is followed by a noun phrase, while the two earlier becauses are followed by clauses.

So what's wrong with C? (1) It changes the meaning slightly. According to the original, the purpose of the extra funds was to make each school unique (whatever their actual affect), while according to C the extra funds did make each school unique (whatever they were intended for). (2) It is awkward. In particular, the usual direct object of the verb allocate is the stuff being allocated rather than person/agency/whatever receiving the stuff. But In C, the direct object of allocate is it (whose antecedent is each school) rather than the more standard funds.

Since vandygrad11 mentioned active/passive voice, I should point out a few thing:
-Answer A, the OA, is also in the passive voice, so voice doesn't seem to be the problem here.
-Standard Written English allows parallel clauses to have different voices, and in fact that's inevitable here, since the first of the parallel clauses (parents and teachers were given major roles) is passive, while the third (the federal judge enforced desegregation orders) is active. Neither of those is underlined, so neither of those will change, so were stuck with different voices.
-Different voices actually make sense here, since neither the parents nor the funds are agents in their clauses, while the judge is the agent in his.
-It's true that active is usually better than passive, but there are plenty of exceptions.
-It's true that consistent voice is better, but there are exceptions.
-Voice is not usually dispositive anyway. When passive is wrong, it's usually because the passive voice creates a distinct error. For instance, Thirsty after a long day of yard work, I drank the whole pitcher of lemonade. is better than Thirsty after a long day of yard work, the whole pitcher of lemonade was drunk by me. because according to the first I was thirsty, while according to the second, the pitcher of lemonade was thirsty.