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': "Metastasis not'ound in - \nSelect and explain. \nA. Femur, B. Humerus, C. Fibula, D. Spine", 'role': 'user'}, {'content': 'Answer: C \nExplanation: Extremities distal to elbow and knee are least commonly involved in metastasis.\n\n\nFibula is distal to knee.', 'role': 'assistant'}]