When the heart is in fibrillation, A) there is no contraction of the myocardium. B) effective pumping of the ventricles ceases because the myocardial cells fail to work as a team, and the brain cannot get adequate oxygen. C) the myocardial cells may become damaged from contracting too fast. D) the myocardial cells deplete their oxygen supply because they are contracting too fast, and the lactic acid produced damages the myocardial cells. E) the myocardial cells are contracting together as they should; fibrillation indicates a normal sinus rhythm of 75 beats per minute.