The correct option is A C - vena cava - takes blood from body parts to the right auricle, Pco2 = 45 mm Hg
In the given figure: A is pulmonary vein which brings pure blood from lungs to the left atrium, B is dorsal aorta which carries blood from heart to body parts, C is vena cava which carries impure blood from body parts to right auricle, and D is pulmonary artery which takes impure blood from heart to lungs.