Which blood vessel is responsible for draining blood from the head, neck, and arms?

The superior vena cava is the correct answer because it specifically serves the vital function of transporting deoxygenated blood from the upper parts of the body—namely, the head, neck, and arms—back to the heart, specifically into the right atrium. This large vein collects blood from smaller veins, such as the subclavian and jugular veins, that drain these areas.

In contrast, the inferior vena cava is responsible for draining blood from the lower body, including the legs and abdominal region, and does not serve the upper body. Pulmonary veins are tasked with carrying oxygenated blood from the lungs back to the heart, and the aorta is the main artery that carries oxygen-rich blood away from the heart to the rest of the body. Hence, these other vessels do not fulfill the function of draining blood from the head, neck, and arms, making the superior vena cava the key vessel for this particular role.