Cyclostomata, like lamprey eels and hagfish, a. feed on other fish or invertebrates b. have cartilage skeletons c. reproduce by internal fertilization
b. have cartilage skeletons
Cyclostomata is a group of Agnatha class. It comprises of jawless fish species like lampreys and hagfishes. They have jawless mouth, epidermal structure that function as teeth. The name Cyclostomata suggests round mouth. The fertilization and development in these fishes is external to the body and the offspring do not get the parental care. These animals are cold blooded and exhibit a cartilaginous skeleton. They have two chamber heart. They feed on other fishes and mammals.
it may be A but im am not so sure but anyways.
they have cartilage skeleton
hope it helps