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
All of the following are Anticholinesteroses used in Alzheimer's disease except 
Select and explain. 
A. Rivastimine, B. Galantamine, C. Memantine, D. Donepezil
C: Memantine
Answer: C: Memantine 
Explanation: Memantine is used to treat Alzeihmer's disease but it is not an anticholinesterase.It acts by blocking NMDA receptors.