Answer:
Option (b).
Step-by-step explanation:
Demyelinating disorders can be defined as diseases that result in destruction of damage of myelin sheath of nerve fibers. Multiple sclerosis is a demyelinating disease, in which myelin sheath is attacked by body's immune cells.
Myelin sheath provides protective covering, acts as insulating layer and allows fast and efficient electrical impulse transmission. Hence, damage to myelin sheath leads to slower rate of conduction of action potential or no action potential.
Thus, the correct answer is option (b).