I usually solve such questions with
Ellipsis approach :-
Whatever is omitted or apparently omitted in the comparison should be present in the sentence somewhereSo with the above points in mind, let's solve this question :-
Members of the current Parliament still expect to perform better than their immediate predecessors have, but they no longer believe they will accomplish as much as first predicted when they took office.
A) still expect to perform better than their immediate predecessors have
(performed)but performed is not present in the sentence, to perform is, hence can not be correct B) still expect to perform better than their immediate predecessors ->
CorrectC) still expect to perform better than their immediate predecessors had
(performed) but performed is not present in the sentence, to perform is, hence can not be correct D) are still expecting to perform better than their immediate predecessors had
(performed) but performed is not present in the sentence, to perform is, hence can not be correct E) are still expecting to perform better than did their immediate predecessors
[color=#00aeef]this sentence is ambiguous as "did" can be either expect or perform; than immediate predecessors expected or than immediate predecessors performed