I think B. Parody.
An understatement is the presentation of something as being smaller, worse, or less important than it actually is. So it's not humorous.
Irony is the expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect.
Satire is the use of humor, irony, exaggeration, or ridicule to expose and criticize people's stupidity or vices, particularly in the context of contemporary politics and other topical issues.
But Parody is an imitation of the style of a particular writer, artist, or genre with deliberate exaggeration for comic effect.
I think Parody goes best with your question.
