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': 'The inhalational bronchodilator with long duration of action is: \nSelect and explain. \nA. Salbutamol, B. Theophylline, C. Ipratropium bromide, D. Tiotropium bromide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Tiotropium\xa0bromide :\nA\xa0newer congener of ipratropium\xa0bromide which binds very tightly\xa0to bronchial\xa0M1 / M3 muscarinic receptors producing long\xa0lasting\xa0bronchodilatation.\nReference: Essentials of Medical Pharmacology Eighth Edition KD\xa0TRIPATHI\xa0page no 128', 'role': 'assistant'}]