Final answer:
The heart is the organ that receives blood from both venae cavae and coronary arteries in the circulatory system.
Step-by-step explanation:
The heart is the organ that receives blood from both venae cavae and coronary arteries in the circulatory system.
The right side of the heart receives deoxygenated blood from the venae cavae, which are the major veins that carry deoxygenated blood from the body to the heart. The left side of the heart receives oxygenated blood from the coronary arteries, which are the blood vessels that supply oxygenated blood to the heart muscle.
Therefore, the correct answer is a. Heart.