The only vein that carries oxygenated blood is:

Correct answer: (c) Pulmonary vein

Explanation

The pulmonary vein is the only vein carrying oxygenated blood, transporting it from the lungs to the left atrium of the heart.

This is an exception, since veins normally carry deoxygenated blood back to the heart, as the cystic, cardiac and hepatic portal veins do.