Jawless Vertebrates — Hagfishes and Lampreys — Lack Myelin

Jawless vertebrates — hagfishes and lampreys — lack myelin.From this you might deduce that

A) immune defenses are compromised in the nervous systems of these fishes.
B) these fishes lack astrocytes.
C) their action potentials are conducted more slowly than in other vertebrates.
D) these fishes are susceptible to multiple sclerosis.
E) their synapse activity is slower than in other vertebrates.