Which of the Following Arguments Commits the Ad Hominem Fallacy

Which of the following arguments commits the ad hominem fallacy?

A) Laura says that gambling on sports should be illegal, but she is an idiot.
B) Animals should have the same rights as humans since they can feel pain.
C) Daily exercise is important because it improves health.
D) Frank thinks that higher education is becoming too expensive, and I agree.
E) If Lenny believes that, then he's a fool.And he does believe it.So he's a fool.