Answer: C) a tube of cartilage (surrounding the notochord) with dorsal projections on both sides of the spinal cord.
Step-by-step explanation:
The hagfish has a skeleton which do not consists of bones instead it consists of cartilage. The cartilage forms the part of the tentacles, tongue, nasopharyngeal duct, and soft palate. The tube of cartilage forms the surrounding of the notochord. It also has an attach with the dorsal projections on both sides of the spinal cord.