The correct answer is d) osteocytes.
Osteocytes are the mature bone cells that become trapped in small cavities known as lacunae. They originate from osteoblasts, which are responsible for bone formation. Once osteoblasts finish their bone-building activity, some of them become encased in the mineralized matrix they produce, transforming into osteocytes. These cells help maintain the bone tissue and communicate with other bone cells to regulate mineral content and the overall health of the bone.