The correct answer is: A. Pulmonary Veins
Oxygenated blood flows through the pulmonary veins. The pulmonary veins are four veins that carry oxygenated blood from the lungs to the left atrium of the heart. The pulmonary veins are located in the thoracic cavity, behind the heart. They are thin-walled and have a smooth, muscular lining. The pulmonary veins are about 2 cm long and 0.5 cm in diameter.
The pulmonary veins are named according to the lung they drain: the right pulmonary veins drain the right lung, and the left pulmonary veins drain the left lung. The pulmonary veins enter the left atrium of the heart at the base of the heart.
The pulmonary veins are important because they carry oxygenated blood to the heart. The heart then pumps the oxygenated blood to the rest of the body.
Pulmonary arteries carry deoxygenated blood from the heart to the lungs.
Both A and B is incorrect because oxygenated blood flows through the pulmonary veins, not the pulmonary arteries.
None of the above is incorrect because oxygenated blood does flow through a vessel, the pulmonary veins.