This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: Orthopaedics
[{'content': 'Classification system of bone tumors is - \nSelect and explain. \nA. Enneking, B. Manchester, C. Edmonton, D. TNM', 'role': 'user'}, {'content': 'Answer: A \nExplanation: According to Ennecking staging of benign tumors Stage 1-latent Stage2-active Stage3-inactive REF : MAHESWARI 9TH ED', 'role': 'assistant'}]