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': 'Directly acting cholinergic drug is/are: \nSelect and explain. \nA. Pilocarpine., B. Bethanechol., C. Methacholine., D. All of the above.', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Directly acting\n\nAch\nPilocarpine\nBethanechol\nMethacholine\nCarbachol', 'role': 'assistant'}]