Composition of bone marrow is

The correct option is **adipose, areolar tissue and blood**.

Bone marrow is a complex, semi-solid tissue found within the spongy (cancellous) portions of bones. It serves as the primary site for hematopoiesis (the production of blood cells) and contains a mixture of different tissue types and cellular components that support this function.

The major constituents of bone marrow include:
1. **Adipose Tissue:** Commonly known as fat tissue, adipose tissue is a major component of yellow bone marrow. It serves as an energy reserve and helps fill the cavities within the bone.
2. **Areolar Tissue:** This is a type of loose connective tissue that forms a supportive framework (stroma) inside the bone marrow cavity. It contains fibers and cells that hold the vascular and hematopoietic components in place.
3. **Blood and Hematopoietic Cells:** Bone marrow is highly vascularized, containing a rich network of blood vessels (sinusoids) along with blood stem cells, developing blood cells (red blood cells, white blood cells, and platelets), and mature blood cells ready to enter circulation.

Therefore, the composition of bone marrow is best described as a combination of adipose tissue, areolar tissue, and blood.