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: Orthopaedics
[{'content': 'An old lady had history of fall in bathroom once and could not move afterwards, she had led in externally rotated position, there was tenderness in scarpas triangle, no hip fracture was seen on x - ray, next step is \nSelect and explain. \nA. CT, B. MRI, C. USCT, D. PET scan', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]