The correct answer to the question is:
C. Ossification
Ossification is the process by which cartilage turns into hard adult bones. During ossification, osteoblasts (bone-forming cells) replace the cartilage with bone tissue. This process is essential for bone growth, repair, and remodeling throughout life. Ossification occurs in two main forms: intramembranous ossification, which is the formation of flat bones like the skull, and endochondral ossification, which is the process of turning cartilage into bone, as seen in long bones like the femur.
