The correct option is A Mesonephros
The mesonephric kidney is one of the excretory organs in vertebrates. It serves as the main excretory organ of aquatic vertebrates such as fishes and as a temporary kidney in reptiles, birds and mammals. It arises from pronephros. Pronephros is the first stage of kidney development in invertebrates. Metanephros is the permanent embryonic kidney in vertebrates. Holonephros is the larval kidney in cyclostome.
Thus, the correct answer is option A.