This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ohopedics Oncology, Subject name: Orthopaedics
[{'content': 'Which of the following is not a benign bone tumor? \nSelect and explain. \nA. Osteoid osteoma, B. Chondroma, C. Enchondroma, D. Chordoma', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Chordoma is a slow growing malignant tumor arising from notochordal remnants. Late pulmonary metastasis can occur in 9% of cases.', 'role': 'assistant'}]