Consider the question. These belong to the class of creature that were the first true tetrapods:
Options:
- (A) millipede
- (B) crabs
- (C) four limbs
- (D) bullfrogs
- (E) gastropod
- (F) a fish
- (G) warm-blooded
- (H) insects
 What is the step-by-step reasoning process to arrive at the answer: (D)?

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Amphibians are the first true tetrapods, or vertebrates with four limbs. Bullfrogs eat other amphibians. Bullfrogs are of the class of creatures that were the first true tetrapods.