Answer:
A. cnidarians
Step-by-step explanation:
Comb jellies are most closely related to Cnidarians. Cnidarians are marine invertebrate organisms which make use of their cnidocytes filled with tentacles in catching preys.
They also have body parts such as the ectoderm and endoderm and a characteristic middle jelly layer called the mesoglea which is similar in a comb jelly.
Examples of Cnidarians include sea anemones and corals.