Which of the following statements is correct for human heart?

During ventricular systole, the AV valves close due to increased pressure.

‘Dub’ sound is associated with closure of semilunar valves at the end of ventricular systole.

Decline in ventricular pressure causes closure of semilunar valves.

The AV valves open even before atrial systole. During the ventricular diastole, the ventricles relax. When ventricular pressure drops below atrial pressure, the AV valves open, and ventricular filling begins.