Answer:
A.
Explanation:
Human heart is an organ that is responsible for the circulation of blood throughout the body and works in a systematic pathway.
The human heart recieves blood from two large veins, the superior and inferior venae cavae and enters through different chambers in the heart that is first at right atrium to right ventricle, from right ventricle to left atrium, then from left atrium pumped into the left ventricle.
The blood first enters into arteries and than move to narrorwer to arterioles that deliver blood to capillaries of the organ where the oxygen and nutrients from blood are supplied to body cells for metabolism and the deoxygenated blood enters into veins.
Hence, the correct option is "A".