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 leukotriene receptor antagonist used in bronchial asthma is - \nSelect and explain. \nA. Zafirleukast, B. Zileuton, C. Ketotifen, D. Nedocromil', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Zafirleukast", 'role': 'assistant'}]