Read the sentence.
The catapult stood on a platform in the castle's tower before it was destroyed.

Which sentence corrects the vague or ambiguous pronoun it?
The catapult stood on a platform in the castle's tower before the tower was destroyed.

The catapult stood on a platform in the castle's tower, and it was destroyed.

The catapult stood on a platform in the castle's tower before something was destroyed.

The catapult stood on a platform in the castle's tower before they were destroyed.