The correct option is B Both A and B
The Gastrotricha is the phylum of animal kingdom which consists microscopic ventrally flattened animals commonly referred to as hairybacks. They are pseudocoelomate animals and found in freshwater and marine environments. The excretory system consists of protonephridia that rid the animal's body of excess water and some metabolic wastes. The protonephridia of gastrotrichs have cells, known as solenocytes. Hence, option D is correct.