Which of the following is a type of calcium channel blocker?

Amlodipine is indeed a type of calcium channel blocker. It works by inhibiting the entry of calcium ions into vascular smooth muscle and cardiac muscle cells, which leads to relaxation of these muscles and results in decreased vascular resistance and lower blood pressure. This action is particularly useful in treating hypertension and angina, as it improves blood flow and reduces the workload on the heart.

In contrast, enalapril is an angiotensin-converting enzyme (ACE) inhibitor, which lowers blood pressure by decreasing the production of angiotensin II, a hormone that causes blood vessels to constrict. Hydrochlorothiazide is a thiazide diuretic that helps lower blood pressure by promoting the excretion of sodium and water through the kidneys. Metoprolol is a beta-adrenergic blocker, which reduces heart rate and cardiac output by blocking the action of certain chemicals on the heart. These mechanisms differ from that of calcium channel blockers, highlighting why amlodipine is correctly identified as a calcium channel blocker.