This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parasympathetic System & Glaucoma, Subject name: Pharmacology
Anticholinesterases drugs are used in :- 
Select and explain. 
A. Alzheimer's disease, B. Multiple sclerosis, C. Guillain Barre syndrome, D. To produce mydriasis
A: Alzheimer's disease
Answer: A: Alzheimer's disease 
Explanation: ALZHEIMER'S DISEASE : It is a progressive neurodegenerative disorder of old age, primarily affecting cholinergic neurons in the brain. These drugs act by inhibiting acetylcholinesterase, thus increasing the availability and prolonging the action of ACh. Tacrine was the drug of choice for Alzheimer's disease but due to several limitations (frequent dosing requirement, hepatotoxicity, diarrhea), other drugs like donepezil, rivastigmine and galantamine are now the preferred agent. Memantine- For moderate to severe disease Cholinesterase inhibitors and memantine have effect on behavioral and psychiatric symptoms No disease modifying treatment is available at present