Question

the most common primary malignant tumor of bone (osseous tissue) is: multiple myeloma osteoid osteoma osteosarcoma chondrosarcoma

Explanation:

Multiple myeloma is a cancer of plasma - cells not a primary bone tumor. Osteoid osteoma is a benign bone tumor. Osteosarcoma is the most common primary malignant tumor of bone. Chondrosarcoma is a malignant cartilaginous tumor but less common than osteosarcoma as a primary bone malignancy.

Answer:

C. Osteosarcoma