The correct option is A Pronephros
Pronephros are the functional kidney of a frog tadpole. Pronephric cells (of the tadpole) undergo apoptosis and their function is replaced by mesonephros which becomes the functional kidney of the adult frog. Metanephors are the embryonic kidney in vertebrates. Archinephros is an ancestral vertebrate kidney found in hagfish larvae.
Therefore, the correct answer is option A.