Carries deoxygenated blood from the lower limbs and abdominal organs to the right atrium

• A. Inferior vena cava
• B. Superior vena cava
• C. Pulmonary veins
• D. Coronary sinus

Answer: (A)

Understanding venous return from the lower body helps explain why the inferior vena cava is the correct vessel. This large vein collects deoxygenated blood from the legs, pelvis, and abdominal organs and carries it upward to the heart, delivering it directly into the right atrium. From there, blood moves to the right ventricle and then to the lungs for oxygenation. This is different from the superior vena cava, which drains the upper body; the pulmonary veins, which bring oxygenated blood from the lungs to the left atrium; and the coronary sinus, which drains blood from the heart muscle itself into the right atrium. Therefore, the vessel that matches the description is the inferior vena cava.