The answer is letter B.
Cnidaria is a phylum that contains over 10,000 of species of
animals that are found exclusively in aquatic environments. These are
predominantly marine species that have specialized cells called cnidocytes that
are mainly used for catching prey. The structure of their bodies are made up of
mesoglea, a non-living jelly-like
substance and are radially symmetrical with their mouths surrounded by
tentacles that carry the cnidocytes that sting and trap their prey enabling
them to feed and survive.
