The correct answer is rhyme.
Whereas satire does include irony, exaggeration, and often, understatement, what it doesn't include is rhyme. Rhymes are usually used in poetry - and even though many poems can be satirical, here we are talking as satire in the prosaic form, not poetic.
In the form of a text, satire is usually used to mock someone and their characteristics through the use of irony, exaggeration, and sarcasm, but not rhyme.