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': 'Montelukast mechanism of action is? \nSelect and explain. \nA. Competitive inhibitor of leukotriene synthesis, B. Inhibits alpha receptor, C. Beta receptor agonist, D. Non-competitive inhibitor of leukotriene synthesis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANSWER: (A) Competitive inhibitor of leukotriene synthesisREF: Goodman and Gillman\'s 11TH edition p. 478"Zafirlukast and Montelukast are leukotriene receptor antagonists. Leukotriene-modifying drugs act either as competitive antagonist of leukotriene receptors or by inhibiting the synthesis of leukotriene"', 'role': 'assistant'}]