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': 'Zafirlukast acts by blocking the action of : \nSelect and explain. \nA. Prostacyclin, B. Platelet activating factor, C. Leukotriene B4, D. Leukotriene C4/D4', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]