The correct option is B Scaphopoda
Shells can be found in animals that belong to the class Scaphopoda. The animal looks roughly like an elephant's tusk. The organisms open on both the ends. It is much small in size. The organism Dentalium entalis which is recognised by the presence of this type of shell-like body structure is a member of a mollusc class Scaphopoda.
Thus, the correct answer is option B.