Answer :
Answer:
The answer is a. the degeneration of patches of the myelin sheath that causes the transmission of neural messages to be slowed or interrupted.
Explanation:
Multiple sclerosis is a disease in which there is deterioration of the myelin sheath that is around the central nervous system (nerve fibres of the spinal cord, optic nerves, and brain), leading to impairment of nerve impulses, and problems with seeing, speaking, sensing, and moving various parts of the body.