While some academicians believe that business ethics should be integrated into every business course, others say that students will take ethics seriously only if it would be taught as a separately required course.

A) only if it would be taught as a separately required course
B) only if it is taught as a separate, required course
C) if it is taught only as a course required separately
D) if it was taught only as a separate and required course
E) if it would only be taught as a required course, separately

OA: B

What's wrong with options C and D?