The correct option is D All of the above
Cestoda is the name given to a class of parasitic flatworms of the phylum Platyhelminthes, which include tapeworms.
As they are flatworms, all cestodes have a flat body. They have a scolex (head) that attaches to the intestine of the host. The scolex have hooks and suckers that aid in attachment.
The body is composed of successive segments called as proglottids.
Therefore, the correct answer is option D.