Answer the following question: Fact 1: Birds are endothermic tetrapod vertebrates. Fact 2: Legs define Tetrapods. Given the two facts above, what are endothermic vertebrates with legs?

OPTIONS: (I) Birds; (II) mammals; (III) Snakes; (IV) ducks; (V) Lizards; (VI) ants; (VII) long; (VIII) toads;
Answer:
(I)