The correct answer is (b) Circulatory system
The circulatory system transports the oxygen throughout the system. The deoxygenated blood is carried from other parts of the body to the lungs and the exchange of gases takes place. The oxygenated blood from the lungs is carried to other parts of the body. Only 1.5% of oxygen is transported through this system other 96% of the oxygen is transported by combing with pigment called hemoglobin. This hemoglobin also an important of circulatory system that helps in purifying the blood.