Answer: A) Understatement.
Explanation: An understatement is a figure of speech employed by writers or speakers to intentionally make a situation seem less important than it really is. In the given statement we can see illustrated the satirical technique of understatement, because after the speaker says that Tonya sang "the star spangled banner" with perfect pitch, he says that she is an ok vocalist, which seems that is downplaying Tonya's singing abilities.