The correct option is B Echinodermata
Echinoderms are exclusively marine invertebrate, having some interesting features. Their life cycle is usually complex. In most echinoderms, the embryo develops into a planktonic larva with a bilateral symmetry, that attains a pentaradial symmetry in the adult stage. It has been suggested that a pentamerous arrangement of skeletal parts strengthens the animal's skeleton than would, for example, a three-rayed symmetry.