The correct answer is: 1) Emphasize or make readers think about important ideas.
A paradox is a self-contradictory statement, this means it contradicts itslef, it is true and false at the same time.
The most famous paradox is: This statement is a lie. As you can see, it is both saying the true and lying about it's content.
Paradoxes show us thay although using logic in a correct way sometimes the result can be absurd, they are quirks in logic. At the same time, a lot of paradoxes may content a latent truth, so they are used to make the reader think of important ideas in an innovative way.