[quote="Bunuel"]The new sports car is heavier than
usual for a performance automobile, but it is exceptional because of its high-powered engine.
The tense of whole sentence is present tense and hence we need ACTIVE voice in present tense .
(A) usual - not proper comparison . we are comparing sports car with USUAL
(B) it is usual - IT is unnecessary
(C) one usually is - hmmn lets keep it for now
(D) is usual - ohkay nothing wrong keep it
(E) has been usual - never ever will I choose has BEEN - It means NEW sports car has always has been heavier .ITS AWKWARD no proper meaning can be derived from E.
NOW LETS WORK ON OUR SELECTED OPTIONS
(C) - one (sports car ) usually (adverb ) is (present tense ) - Nothing wrong here but it sounds passive and a bit jumbled . often our mind skips such minor difference .
BETTER WAY TO COMPARE -The new sports car is heavier than usually a sports car is ..... this makes sense .
option D - is usual - refers to other sports car --> sports car in general use (other than this new sports car) .THE WORD USUAL IS ACTING AS A VERB . we dont want usually which is adverb .
so when you plug it in question you get
The new sports car is heavier than IS(a sports car normally is IN GENERAL) USUAL for a performance automobile.....
I anyways have no other better option left so D is the winner

.