The correct answer is the pulmonary vein.

• Pulmonary vein
  • The Pulmonary vein is the vein that transfers oxygenated blood from the lungs to the heart.
  • The largest pulmonary veins are the four main pulmonary veins, two from each lung that drains into the left atrium of the heart.
  • The pulmonary veins are part of the pulmonary circulation.
  • The pulmonary veins originate from individual alveoli within the lungs as capillary vessels.

• Superior Vena Cava
  • The superior vena cava is a large valveless vein that conveys deoxygenated blood from the upper half of the body and returns it to the right atrium.
• Hepatic Portal Vein
  • It is a vessel that moves blood from the spleen and gastrointestinal tract to the liver.
  • It is approx 3-4 inches in length and is usually formed by the merging of the superior mesenteric and splenic veins behind the upper edge of the head of the pancreas.
• Renal Vein
  • The renal veins are veins that drain the kidney.
  • They connect the kidney to the inferior vena cava.
  • The blood flowing through the renal vein is deoxygenated and contains nitrogenous waste.