A. atrial diastole (ventricular filling), atrial systole, isovolumetric contraction, ventricular systole (ejection phase), isovolumetric relaxation b. ventricular systole (ejection phase), atrial systole, atrial diastole (ventricular filling), isovolumetric relaxation, isovolumetric contraction c. isovolumetric relaxation, ventricular systole (ejection phase), atrial systole, atrial diastole (ventricular filling), isovolumetric contraction d. none of the above