This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Radiology Q Bank, Subject name: Radiology
[{'content': 'Trethowan sign is used in radiological diagnosis of? \nSelect and explain. \nA. TB Hip, B. Pehes Disease, C. Slipped Capital Femoral Epiphysis, D. Avascular Necrosis of head of femur', 'role': 'user'}, {'content': "Answer: C \nExplanation: TRETHOWAN'S SIGN In normal hip a line drawn tangential to superior femoral neck (Klein's line) intersects small poion of lateral capital epiphyseal. In posterior displacement of epiphyses the line doesn't intersect.", 'role': 'assistant'}]