The correct option is C Right atrium
Between the lungs in the thoracic cavity lies the pear-shaped heart, which pumps blood via blood vessels throughout the body forming the circulatory system. The heart is four-chambered with 2 auricles and 2 ventricles on either sides known as right auricle, right ventricle, left auricle, and the left ventricle respectively. The right auricle receives deoxygenated blood from all parts of the body through the two precaval veins and the postcaval vein. The pulmonary trunk carries this deoxygenated blood from the right ventricle to the lungs. The left auricle receives oxygenated blood from the lungs. This oxygenated blood is carried to the rest of the body organs by the systemic arch (aorta) from the left auricle.