One Limiting Factor in the Ability of Damaged Axons to Regenerate

Multiple Choice

One limiting factor in the ability of damaged axons to regenerate in the brain and spinal cord is that:

A) they don't have any myelin to guide them.
B) they regenerate only one to two millimeters.
C) growing dendrites compete with growing axons.
D) there are no muscles in the brain and spinal cord to guide the growth.