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: Dental
Most common malignant bone tumor in child: 
Select and explain. 
A. Osteosarcoma, B. Ewing sarcoma, C. Metastatic carcinoma, D. Osteoma
A: Osteosarcoma
Answer: A: Osteosarcoma 
Explanation: None