Option 1: Pulmonary vein - This is the correct option. The pulmonary veins carry oxygenated blood from the lungs back to the heart. After the oxygen from inhaled air has been transferred to the blood in the lungs, it is carried by the pulmonary veins to the left atrium and then pumped to the rest of the body.

Option 2: Pulmonary artery - This is incorrect. The pulmonary artery carries deoxygenated blood from the heart to the lungs for oxygenation. It is responsible for transporting blood to the lungs, not carrying oxygenated blood.

Option 3: Hepatic portal vein - This is incorrect. The hepatic portal vein carries blood from the gastrointestinal organs and spleen to the liver for processing, but it does not carry oxygenated blood.

Option 4: Renal vein - This is incorrect. The renal veins carry deoxygenated blood from the kidneys back to the heart. They transport blood that has been filtered by the kidneys, not oxygenated blood.

Therefore, only option 1, the pulmonary vein, is responsible for carrying oxygenated blood.