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: ENT
[{'content': 'A 2-year-old boy presenting with sudden severe dyspnea, most common cause is: \nSelect and explain. \nA. Foreign body, B. Bronchiolitis, C. Asthmatic attack, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In case of stridor with acute airway obstruction (i.e. dyspnea) always history of any foreign body ingestion should be taken.', 'role': 'assistant'}]