The correct option is A Osteoblasts
Osteoblasts are the cells that form new bone. They also come from the bone marrow and are related to structural cells. They have only one nucleus. Osteoblasts work in teams to build bone. They produce new bone called "osteoid" which is made of bone collagen and other protein and osteoclasts, which break down the tissue. Chondrocytes produce all of the structural components of cartilage, including collagen, proteoglycans, and glycosaminoglycans.