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': "The drug used in Alzheimer's disease is \nSelect and explain. \nA. Tacrine, B. Rivastigmine, C. Pyridostigmine, D. Neostigmine", 'role': 'user'}, {'content': 'Answer: B \nExplanation: Tacrine was not discontinued due to hepatotoxicity Donepezil, gallatamine, rivastigmine can be used which are lipid soluble and can cross BBB easily Pyridostigmine and neostigmine are quaernary amines which do not cross BBB hence not used in Alzheimers Ref: KDT 6th ed pg 104', 'role': 'assistant'}]