14. Which of the following statements about the cardiac cycle is TRUE? (A) The duration of systole is greater than that of diastole in a subject at rest. (B) During isovolumetric ventricular relaxation, blood flows from the atria into the ventricles. (C) Closure of the atrioventricular valves occurs at the onset of ventricular systole. (D) The QRS complex occurs at approximately the same time as the closure of the semilunar valves.