This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Asthma, Subject name: Pharmacology
[{'content': 'Mechanism of zileuton: \nSelect and explain. \nA. Cyclooxygenase inhibitor, B. 5-lipoxygenase inhibitor, C. Phosphodiesterase inhibitor, D. Mast cell degranulation', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. 5-lipoxygenase inhibitorZileuton is drug which inhibit the synthesis of leukotrienes as they are chemotactic and causes bronchoconstriction.', 'role': 'assistant'}]