Step 1: Rule for "either...or"
When subjects are joined by “either…or,” the verb agrees with the nearer subject.
Step 2: Applying rule
Here, “he” is the subject closer to the verb, so singular “has” is correct.
Step 3: Eliminating other options
- (a) uses “have” incorrectly for singular “he.”
- (c) changes meaning entirely.
- (d) mismatches number (“they has”).