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': 'All are common causes of stridor except: \nSelect and explain. \nA. Foreign body in larynx and trachea, B. Laryngomalacia, C. Atrophic laryngitis, D. Multiple papillomas of larynx', 'role': 'user'}, {'content': "Answer: C \nExplanation: c. Atrophic laryngitis(Ref: Nelson's 20/e p 2113-2116)Atrophic Laryngitis usually manifests with hoarseness & irritable cough; Rest 3 conditions can manifest as stridor.", 'role': 'assistant'}]