Which among the following is the most common malignancy of bone?

Osteosarcoma is the most frequent bone cancer occurring in children and adolescents aged 10-20 years, whereas in children younger than 10 years, the most common primary bone cancer is Ewing sarcoma. Multiple myeloma is the most common primary neoplasm of the skeletal system. The disease is a malignancy of plasma cells. Osteoid osteoma is a benign bone-forming tumour. Osteoid osteoma is the most common cause of painful scoli- osis in adolescents. Osteochondroma is the most common benign tumor of bone.