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: Pediatrics
[{'content': 'The most common cause of stridor in infant and children is: \nSelect and explain. \nA. Congenital subglottic stenosis, B. Laryngomalacia, C. Vocal Cord Paralysis, D. Foreign body in airway', 'role': 'user'}, {'content': "Answer: B \nExplanation: b. Laryngomalacia(Ref: Nelson's 20/e p 2036; Ghai 8/e p 369)Laryngomalacia is the most common cause of stridor in infants and children.", 'role': 'assistant'}]