OFFICIAL EXPLANATION
As exit polls are used to project the winners of an election, sometimes appearing before all the polling stations are closed, this results in their premature release influencing voters to change their ballot.
(A) As exit polls are used to project the winners of an election, sometimes appearing before all the polling stations are closed, this results in their premature release influencing
Incorrect.
This answer choice is grammatically incorrect. Using two reason conjunctions / phrases (as and this results in) to express the relation between two parts of a sentence is redundant. Only one should be used:
As [exit polls are used to project, sometimes appearing before stations are closed,] [their premature release influences voters]
[exit polls are used to project, sometimes appearing before stations are closed,] ; this results in [their premature release influencing voters](B) Exit polls, used for projecting an election's winners and sometimes appearing before polling stations are closed, result in their premature release influencing
Incorrect.
This answer choice is illogical. Changing the conjugated verb are used into a modifier (used for ...) turns Exit polls into the subject of the verb result. This creates an illogical sentence:
Exit polls, ... , result in their (own?) premature release ...
It is the circumstance of appearing early that has a result, not the exit polls themselves.(C) Used to project the winners of an election, exit polls sometimes appear before all the polling stations are closed with the result that their premature release influences
This answer choice corrects the original redundancy by removing the reason conjunction As at the beginning of the sentence, keeping only one reason phrase (with the result).(D) Exit polls used to project an election's winner sometimes appear before all the polling stations are closed, with the result that their premature release influences
Incorrect.
This answer choice is illogical. Changing the conjugated verb are used into a modifier (used to ...) turns Exit polls into the subject of the verb result. This creates an illogical sentence:
Exit polls, ... , sometimes (a) appear ... and (b) result in their (own?) premature release ...
It is the circumstance of appearing early that has a result, not the exit polls themselves.(E) As exit polls used to project an election's winner sometimes appear before all the polling stations are closed, with the result that their premature release influences
Incorrect.
This answer choice is grammatically incorrect. This answer choice is comprised of two clauses connected by the conjunction As:
As [Jane is a doctor], [she could help the boy]
[Jane could help the boy], as [she is a doctor].
However, by changing this results to with the result, the second clause becomes a fragment, lacking both a subject (previously this) and a conjugated verb (previously results):
As [Exit polls .... appear] , [ with the result that ...]