The statements below could be wrong. Choose the correct sentences! I had send the mail yesterday

The correct answer is 'I had sent the mail yesterday.' The original sentence incorrectly uses the base form 'send' with the past perfect auxiliary 'had.' Past perfect requires the past participle form 'sent.' Option B incorrectly uses 'have send' (present perfect with base form), Option C incorrectly uses simple present 'send' for a past action, and Option D 'have sent' is grammatically correct present perfect but doesn't match the past perfect structure of the original sentence.