The Parthenon is larger than usual for a Doric temple, with the eight columns on the short sides and seventeen on the long ones rather than the typical six and thirteen.
(b) is usual
(c) has been usual
(d) one usually is
(e) it is usual
I think Option is E is more suitable. Here is the reason why
a. Parthenon is not larger than "USUAL"
b. Grammatically incorrect
c. Should have been " That is usual for a doric"
d. "one" doesnt make a difference between a person or place
e. Comparing apples to apples here.
P is larger than " It is usual for a doric temple".