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': 'Most common site for osteomyelitis in adults \nSelect and explain. \nA. Lower end of femur, B. Cervical spine, C. Thoracolumbar spine, D. Upper end of tibia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]