question_answer

Which one of the following groups belongs to one category

A) Polychaeta, hirudinea, oligochaeta and onychophora

B) Holothuroidea, ophiuroidea, asteroidea, echinoidea and hirudinea

C) Turbellaria, trematoda and cestoda

D) Cephalopoda, gastropoda, thysanura and lamelibranchiata