This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'All are chlolinergic agents except \nSelect and explain. \nA. Galantamine, B. Donepezil, C. Tacrine, D. Memantine', 'role': 'user'}, {'content': "Answer: D \nExplanation: Donepezil,rivastigmine,gallantamine and tacrine are cholinergic (due to inhibition of cholinesterase enzyme) drugs useful for alzheimer's disease. Memantine is an NMDA blocker,used for Alzheimer's disease. Ref-KDT 6/3 p472,473", 'role': 'assistant'}]