**Core Concept**
Donepezil is a centrally acting cholinesterase inhibitor used in the management of Alzheimer's disease. It works by increasing the concentration of acetylcholine in the brain, thereby improving cognitive function.

**Why the Correct Answer is Right**
Donepezil selectively inhibits the enzyme acetylcholinesterase, which is responsible for the breakdown of acetylcholine. By inhibiting this enzyme, donepezil increases the concentration and availability of acetylcholine in the synaptic cleft, allowing it to bind to muscarinic and nicotinic receptors. This results in improved cognitive function, memory, and attention in patients with Alzheimer's disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because donepezil does not directly stimulate the nicotinic receptors; it only increases the availability of acetylcholine for them to bind to.
**Option B:** This option is incorrect because donepezil is not a direct agonist of the muscarinic receptors; it only increases the concentration of acetylcholine for them to bind to.
**Option C:** This option is incorrect because donepezil does not directly inhibit the enzyme butyrylcholinesterase; it specifically targets acetylcholinesterase.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that donepezil is only one part of a comprehensive treatment plan for Alzheimer's disease, and its benefits are most pronounced when used in conjunction with other therapies, such as cognitive training and behavioral interventions.

**Correct Answer: C. Inhibition of acetylcholinesterase.**