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': 'Simple bone cyst is common in \nSelect and explain. \nA. Upper end of Humerus, B. Upper end of Radius, C. Upper end of Femur, D. Lower end of Femur', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]