How does the human heart level of organization relate to cells? to organ systems

It is hard to understand this question but ill give you my best answer. The hearts level of organisation to cells is immense, the heart pumps blood to every cell in the body (so they can respire) through a system of Arteries, veins and capillaries. The blood is pushed by the force of the heart through the arteries, the main (and largest) tubes for transportation to segments of the body further away from the heart. This goes into a smaller system of veins that brake off into a tree kind of pattern to reach every cell. These later brake off into the capillaries that have walls only 1 cell thick. This is how blood is transported to each cell that requires energy and oxygen to respire.

The correct answer would be b