The correct option is
D Amphibian
The evolution of tetrapods begins about 400 million years ago in the Devonian period with the earliest tetrapods evolved from lobe-finned fish named Sarcopterygians. Tetrapods are categorized as a biological superclass. Tetrapods which includes all living and extinct birds, reptiles, amphibians, and mammals. So, the correct answer is option D, Amphibian.