Answer:
A. he/I
Step-by-step explanation:
First, try saying it out loud with each one. If it sounds wrong, it probably is. Read this somewhere the other day:
Take away the subject and verb and check afterwards by making the 'he and I' as the subjects instead:
The principal has nominated he and I to represent the school.
He and I are to represent the school.
Usually if it's something like 'he and me' or another pronoun 'and me', then it's going to be wrong.
Hope this helps!