Which class of antihypertensive drugs works by blocking calcium entry into vascular smooth muscle?

Choice A rationale Thiazide diuretics, such as hydrochlorothiazide, lower blood pressure by inhibiting sodium and chloride reabsorption in the distal convoluted tubule of the kidneys. This increases the excretion of water and salt, reducing blood volume and thereby lowering blood pressure. Choice B rationale ACE inhibitors, like lisinopril, lower blood pressure by blocking the conversion of angiotensin I to angiotensin II. Angiotensin II is a potent vasoconstrictor, so inhibiting its formation leads to vasodilation and reduced blood pressure, also reducing aldosterone secretion. Choice C rationale Calcium channel blockers (CCBs) inhibit the influx of calcium ions into vascular smooth muscle and cardiac cells. This leads to the relaxation of the muscle walls, causing vasodilation and a decrease in peripheral vascular resistance, which in turn lowers blood pressure. Choice D rationale Beta-blockers, such as metoprolol, lower blood pressure by blocking the effects of epinephrine and norepinephrine. This leads to a decrease in heart rate, myocardial contractility, and cardiac output, thereby reducing blood pressure. They do not directly block calcium entry into muscle cells.