The correct option is C Coelomate, spiny, marine
Echinoderms are enterocoelous coelomates with pentamerous radial symmetry, without distinct head or brain having a calcareous endoskeleton of separate plates or pieces and a peculiar water vascular system of coelomic origin with podia or tube-feet projecting out of the body. They are exclusively marine and are among the most common and widely distributed marine animals. Spines are directed downward often forming hooks or spiny clubs.