Correct Option: B

Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nares, scales, a twochambered heart, and skeletons made of cartilage rather than bone. The cartilaginous fish are so named because their skeleton is composed of cartilage which is not reinforced by the minerals that make bone. It includes elasmobranchs: sharks, rays and skates, etc.