Solution

Sea anemones are a group of water-dwelling, predatory animals which belong to the order Actiniaria. They are named after Anemone which is a terrestrial flower. Sea anemones are classified in the phylum Coelenterata, class Anthozoa. They have large polyps that allow for digestion of larger prey and also lack a medusa stage. Many sea anemones form symbiotic relationships with single-celled dinoflagellates.
Therefore, the correct answer is option C.