At the beginning of the cardiac cycle, which of the following occurs?

The atria and ventricles are in diastole, and the atrioventricular valves are open.

The atria are in systole, the ventricles are in diastole, and the semilunar valves are open.

The atria and ventricles are in systole, and all valves are open.

The atria and ventricles are in diastole, and the semilunar valves are open.