This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
[{'content': "One of the following is a reversible cause of dementia : \nSelect and explain. \nA. Toxic dementia, B. Alzheimer's ds., C. Multi - infarct dementia, D. Pick ds", 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Toxic', 'role': 'assistant'}]