The new sports car is heavier than <usual> for a performance automobile, but it is exceptional because of its high-powered engine.
B) it is usual
C) one usually is
D) is usual
E) has been usual
I think, this one is from OG.
this checks the parallelism. ...is heavier...is usual. The actual sentences reads that 'new sports car is heavier than usual for a car', it is not clear what is usual for a car (bad: What usual for a car
). need a verb here to make it a clear referent.