In the autonomic regulation of blood pressure (a) Cardiac output is maintained constant at the expense of other hemodynamic variables (b) Elevation of blood pressure results in elevated aldosterone secretion (c) Baroreceptor nerve fibers docrease firing rate when arterial pressure increases (d) Stroke volume and mean arterial blood pressure are the primary direct determinants of cardiac output (e) A condition that reduces the sensitivity of the sensory baroreceptor nerve endings might cause an increase in sympathetic discharge