• (a) is incorrect as the right atrium receives deoxygenated blood via the vena cava, not oxygenated blood from the pulmonary artery.
• (b) is correct as the left atrium transfers oxygenated blood to the left ventricle, which pumps it to the body.
• (c) is incorrect as it misstates the role of vena cava in relation to the right atrium.
• (d) is correct as the left atrium transfers oxygenated blood to the aorta, which distributes it to different body parts.