I'll give you a question, please answer with step-by-step reasoning process.
The person answered the door when the mailman knocked, what likely happened next?\nOptions:\n- arm himself\n- cross street\n- feel sleepy\n- dog barked\n- receive mail

receive mail
Mailman is a person who brings mail.

When a mailman comes to one's door, the person usually receives mail.

.

So, the answer is receive mail