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: Pharmacology
55yr old man with dementia was given a natural alkaloid which of the following? 
Select and explain. 
A. Tacrine, B. Donepezil, C. Galantamine, D. Rivastigmine
C: Galantamine
Answer: C: Galantamine 
Explanation: Ans. is 'c' i.e., Galantamine Galantamine: It is a natural alkaloid which selectively inhibits cereral acetylcholinesterase and has some direct agonistic action on nicotinic receptors as well. It has produced cognitive and behavioural benefits in alzheimers disease.