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
Leukotriene receptor antagonist used for bronchial asthma 
Select and explain. 
A. Zafirkulast, B. Zileuton, C. Cromolyn Sodium, D. Aminophylline
A: Zafirkulast
Answer: A: Zafirkulast 
Explanation: Refer KDT 6 /e p 222 Montelukast, zafirlukast and idalukast are Cys-LT, receptor antagonist Zileuton inhibits the production if Leukotriene by inhibiting the enzyme 5-lipoxygenase