This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Pharmacology
[{'content': 'Theophylline is a \nSelect and explain. \nA. Mast cell stabilizer, B. Leukotriene antagonist, C. Phosphodiesterase inhibitor, D. Leukotriene synthesis inhibitor', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Theophylline- Phosphodiesterase inhibitor (inhibit the degradation of CAMP) Sodium cromoglycate is a mast cell stabilizer used for prophylaxis of asthma Montelukast and zafirlukast are leukotriene antagonist Zileuton is a LOX inhibitor', 'role': 'assistant'}]