The correct option is B Red bone marrow
The bone marrow produces the cellular elements of the blood, including platelets, red blood cells and white blood cells. Red marrow is found in the flat bones, such as the pelvis, sternum, cranium, ribs, vertebrae and scapulae, and in the cancellous material at the epiphyseal ends of long bones such as the femur and humerus. Platelets which are a part of blood are produced in the red bone marrow along with many other cells.