Final answer:
The spouse understands that Donepezil (Aricept) treats the symptoms of Alzheimer's disease.
Step-by-step explanation:
The spouse of the client with Alzheimer's disease (AD) demonstrates an understanding of the nurse's instructions by stating that Donepezil (Aricept) will treat the symptoms of Alzheimer's disease (Option A). Donepezil is a cholinesterase inhibitor that helps increase the levels of acetylcholine in the brain, improving communication between neurons and slowing the progression of symptoms. Memantine (Namenda), mentioned in Option B, is also used to treat Alzheimer's disease, but it is primarily indicated for moderate to severe symptoms.