One Characteristic of the Class Holothuroidea Is

One characteristic of the class Holothuroidea is:

A) that most are predators that consume partially digested prey.
B) that most of the species are extinct.
C) that they have a reduced endoskeleton consisting of microscopic plates embedded in the body wall.
D) that moveable spines are used to facilitate locomotion.
E) that they have a distinct central disk with very long, slender arms.