( A ) the ventricular pressure further declines the tricuspid and bicuspid valves are pushed open by the pressure in the atria exerted by the blood which was being emptied into them by the veins
( B ) none of the above
( C ) the ventricular pressure falls causing the closure of semilunar valves
( D ) closure of semilunar valves prevents the backflow of blood into the ventricles
