While Reviewing the Case File of an Older Adult Client

While reviewing the case file of an older adult client, the nurse finds the client's vitamin B₁₂ deficiency is untreated. Which physiological change in the nervous system does the nurse suspect to cause gait instability and paresthesia in the client?

A) Degeneration of neurons
B) Lack of acetylcholine in the hippocampus lobe
C) Abnormalities in the basal ganglia of the midbrain
D) Demyelination of the dorsal columns of the spinal cord