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': 'Ipratropium bromide used in bronchial asthma, is : \nSelect and explain. \nA. β-Sympothomimetics, B. Methylxanthines, C. Anticholinergics, D. Mast cell stabilizers', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]