The drug most likely to be used in a patient with high renin hypertension is a type of medication called an ACE inhibitor. Therefore, the correct answer is a) Prindopril. ACE inhibitors work by blocking the production of a hormone called angiotensin II, which causes blood vessels to narrow and can increase blood pressure. By blocking the effects of angiotensin II, ACE inhibitors help to widen blood vessels, lower blood pressure, and reduce the workload on the heart. In patients with high renin hypertension, which is characterized by high levels of renin (a hormone that regulates blood pressure) in the blood, ACE inhibitors are particularly effective in reducing blood pressure.