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
[{'content': '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 \nSelect and explain. \nA. Acetylcholine, B. Dopamine, C. Neuropeptide Y, D. Nitric oxide', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .', 'role': 'assistant'}]