Answer:
b) aorta
Explanation:
On contraction of the atrium, the atrioventricular valves open and push blood to their respective ventricles. Oxygenated blood from the left atrium moves to left ventricle. On contraction of ventricles, semilunar valves open and oxygenated blood from left ventricles is pushed into the aorta, a major artery which distributes blood to the body cells through different arteries.