Solution

The Bivalvia were referred as the Lamellibranchiata and Pelecypoda long ago. They are comprised of the class of marine and freshwater molluscs. They have bodies which are compressed from both the sides. The body of this organism is enclosed by a shell. The shell is made up of two covers consisting of two hinged parts. They have no head and they also lack a radula. Bivalves include clams, oysters, mussels, and numerous other families. These are organisms that live in saltwater as well as in freshwater.
Thus, the correct answer is option C.