Correct Answer:
B. Would have helped
Correct answer: Would have helped. This is a third conditional (unreal past), so the main clause takes “would have + past participle”.
Background: “Had he been” is the inverted form of “If he had been”.
- Would help: “Would help” is the form for a present or future unreal condition.
- Would has helped: “Would has” is ungrammatical.
- None of these: “None of these” is incorrect because “would have helped” is correct.
Did you know? The third conditional talks about situations that did not happen.
Memory trick: Had + past participle → would have + past participle.