Help the disappointed guest finish their text message.

The party was a complete disaster! I knocked on the door for ten minutes, but ___ answered.

The correct answer is nobody.

We use nobody to talk about an absence of people. Since the guest is waiting for a person to answer the door, "nobody" is the right choice! We don't use "anybody" here because the verb "answered" is positive; "anybody" would need a negative verb (like "didn't answer").