Answer: B. capable of producing blood cells.
Explanation: Red bone marrow is the anatomical structure that safeguards hematopoietic stem cells, which are crucial progenitors of a diverse array of blood cells comprising erythrocytes, leukocytes, and thrombocytes. Spongy bone tissue is discernible within relatively large bones, such as the pelvis, sternum, and skull, in both adult and pediatric populations. Red bone marrow is known to be abundant in the skeletal system of children; notwithstanding, it remains present in the bones of adults, albeit with a tendency to be displaced by yellow bone marrow as we progress in age.