This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
Persons with mild cognitive impairments who smoke may experience a worsening of symptoms if they stop smoking. This worsening of symptoms is because nicotine acts as an agonist for receptors of a paicular neurotransmitter. That neurotransmitter is 
Select and explain. 
A. Acetylcholine, B. Dopamine, C. Neuropeptide Y, D. Nitric oxide
A: Acetylcholine
Answer: A: Acetylcholine 
Explanation: .