Cardiopulmonary Bypass Path

Steps:

• Blood enters the heart from the body via the vena cava, carrying deoxygenated blood.
• The bypass machine diverts this blood, oxygenates it, and acts as heart and lungs.
• Oxygenated blood must return to the systemic circulation to reach the body.
• The aorta is the vessel leaving the heart to distribute oxygenated blood to the body.

Why A is correct:

• Vena cava delivers deoxygenated blood to the right atrium; aorta carries oxygenated blood from the left ventricle to the body, matching the machine's oxygenation and pumping role.

Why the others are wrong:

• B: Pulmonary artery carries deoxygenated blood to lungs, not body.
• C: Pulmonary vein returns oxygenated blood from lungs to heart, not to body.
• D: Reverses flow; vena cava receives from body, not delivers to it.

Final answer: A