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': 'Steeple sign is seen in: \nSelect and explain. \nA. Croup, B. Acute epiglottitis, C. Laryngomalacia, D. Quinsy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: In radiology, the steeple sign is a radiologic sign found on a frontal neck radiograph where subglottic tracheal narrowing produces the shape of a church steeple within the trachea itself. The presence of the steeple sign suppos a diagnosis of croup, usually caused by paramyxoviruses.', 'role': 'assistant'}]