the organism is a free-living one that is anchored one that is anchored to the bottom of ponds and streams. What is the common name of the group to which this organism belongs?

A.cnidarians

B.flatworms

C.porifera

D.annelids

If you get it thanks for the help!

Cnidarian is a phylum of organisms that comprises of the simplest forms of multicellular organisms. Examples of cnidarians includes; coral animals, jellyfish, and sea anemones among others.
They are soft-bodied, carnivorous animals that have stinging tentacles arranged in circles around their mouths. They are the simplest animals to have body symmetry and specialized tissue.
All cnidarians are aquatic, mostly marine organisms, and have two body layers that is the ectoderm and endoderm.

the organism is a free-living one that is anchored one that is anchored to the bottom of ponds and streams. What is the common name of the group to which this organism belongs?A.cnidariansB.flatworms C.poriferaD.annelidsIf you get it thanks for the help!