Explanation:
C
Stinging capsule (Nematocysts) are the organs of offence and defence, present in the phylum Coelenterata. Sea pen and Sea fan are members of this phylum.
- Nematocysts have specific capsules known as cnidoblasts cell. They have most common intracellular secretion products. Nematocysts belong to the phylum Coelenterata. In coelentrates, a cavity called coelentron or gastrovascular cavity is present with single opening calledmouth, this cavity help in digestion and circulation.