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
All of the following cause subcoical dementia, Except: 
Select and explain. 
A. Alzheimer's disease, B. Porkinsonism, C. HIV encephalopathy, D. Progressive Supranuclear palsy
A: Alzheimer's disease
Answer: A: Alzheimer's disease 
Explanation: 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.