If brain size is positively correlated with intelligence, the giant stegosaurus, ... ...

If
A
brain size is positively
correlated
B
with intelligence, the giant stegosaurus, with a brain the size of a nut,
must of
C
had difficulty
fending off
D
the vicious carnivores of the Jurassic period.
No Error
E

(A)
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in 07. Idioms