Final answer:
Mrs. Samuels is suffering from multiple sclerosis which affects the myelin sheath that insulates neurons, leading to difficulty in moving.
Step-by-step explanation:
Mrs. Samuels is suffering from multiple sclerosis (MS), a disease that primarily targets the myelin sheath of neurons in the central nervous system. This degradation leads to impaired signal transmission, resulting in various symptoms such as muscle weakness, difficulty with coordination and balance, and sensations like numbness. The correct answer to the question is, therefore, c. the myelin sheath; moving.
This is because the myelin sheath is critical for the proper conduction of electrical signals along the nerve fibers, and when damaged, it leads to a significant reduction in the ability to move, among other neurological symptoms. It does not primarily impair hearing, which can be affected in cases of auditory nerve damage or ear structure damage but not usually as a direct consequence of MS.