JBL EMT Practice Exam

The common iliac vein is the correct answer because it is responsible for draining deoxygenated blood from the abdomen, pelvis, and lower extremities and returning it to the right atrium. The coronary sinus vein and superior vena cava both drain oxygen-rich blood and do not carry deoxygenated blood. The inferior vena cava does carry deoxygenated blood, but it also receives blood from the abdominal organs and lower extremities, not just the abdomen, pelvis, and lower extremities as stated in the question.