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
[{'content': 'Which of the following drug binds only with the anionic site of cholinesterase ? \nSelect and explain. \nA. Physostigmine, B. Neostigmine, C. Edrophonium, D. Pyridostigmine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Physostigmine, neostigmine and pyridostigmine are carbamates\xa0by chemical nature, they bind to both esteritic as\xa0well as anionic site whereas edrophonium is an alcohol\xa0and binds to anionic site only.', 'role': 'assistant'}]