Able Was in a Skiing Accident and Injured His Spinal

Able was in a skiing accident and injured his spinal cord.Unfortunately,the doctors had to tell him that he won't walk again.He decides to do his own research into possible treatment for spinal cord injuries,and finds one new area of research that looks very promising.What did Able learn on his own?

A) Schwann cells and their ability to regenerate neuron axons in the PNS
B) efferent fibres that can re-grow with prolonged, mild electrical stimulation
C) diverting spinal reflexes to generate voluntary movement
D) stem cells that increase the myelin production around the spinal cord