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: Medicine
[{'content': "All of the following cause subcoical dementia, Except: \nSelect and explain. \nA. Alzheimer's disease, B. Porkinsonism, C. HIV encephalopathy, D. Progressive Supranuclear palsy", 'role': 'user'}, {'content': "Answer: A \nExplanation: Answer is A (Alzheimer's disease):` Dementia from Alzheimer's disease (Dementia of Alzheimer's Type) is the classical proto-type of coical dementias. Alzheimer's dementia is the most common coical dementia.", 'role': 'assistant'}]