Final answer:
The pulmonary vein does not return blood to the right atrium of the heart, as it carries oxygenated blood from the lungs to the left atrium. Instead, the superior and inferior venae cavae and the coronary sinus return deoxygenated blood to the right atrium.
Step-by-step explanation:
The option that does NOT return blood to the right atrium of the heart is the pulmonary vein. The right atrium receives deoxygenated blood from the systemic circuit through the superior vena cava, inferior vena cava, and the coronary sinus. The pulmonary veins, however, carry oxygenated blood from the lungs to the left atrium of the heart, which is why option A, the pulmonary vein, does not return blood to the right atrium. Regarding the order of blood flow from the heart, out to the body, and back again, the sequence is: arteries, capillaries, venules, veins, and then back to the heart through the venae cavae into the right atrium.