Which of the following correctly gives the orders of events in a cardiac cycle?
A) Atria contract, ventricles contract, AV valves close, ventricles relax, semilunar valves close
B) Ventricles contract, AV valves close, atria contract, ventricles relax, semilunar valves close
C) Ventricles relax, atria contract, ventricles relax, AV valves close, semilunar valves close
D) AV valves close, ventricles relax, atria contract, semilunar valves close, ventricles contract