Which of the following animal groups is incorrectly paired with its characteristic?

• A

  Porifera : Central cavity called spongocoel lined by choanocytes

• B

  Mollusca : The body is covered by a chitinous exoskeleton

• C

  Cnidaria : Gastro-vascular cavity with a single opening, mouth on hypostome

• D

  Arthropoda : Jointed appendages help in locomotion