**Core Concept**
ACE inhibitors are a class of medications used to treat hypertension and heart failure by blocking the conversion of angiotensin I to angiotensin II, a potent vasoconstrictor. This action leads to vasodilation, decreased peripheral resistance, and reduced blood pressure. ACE inhibitors also have a protective effect on the kidneys by reducing proteinuria and slowing the progression of renal disease.

**Why the Correct Answer is Right**
ACE inhibitors are contraindicated in patients with bilateral renal artery stenosis, as they can further reduce blood flow to the kidneys, exacerbating renal failure. This is because ACE inhibitors rely on the renin-angiotensin-aldosterone system (RAAS) to maintain renal perfusion. Blocking ACE can lead to a decrease in angiotensin II, which normally helps to constrict the efferent arteriole and maintain glomerular filtration rate (GFR) in the setting of renal artery stenosis.

**Why Each Wrong Option is Incorrect**
**Option A:** ACE inhibitors are not true antihypertensives, as they work through a different mechanism. **Incorrect**, as ACE inhibitors are indeed antihypertensives by virtue of their vasodilatory effects.

**Option B:** ACE inhibitors are not effective in treating hypertension in patients with chronic kidney disease. **Incorrect**, as ACE inhibitors have been shown to reduce proteinuria and slow the progression of renal disease in patients with chronic kidney disease.

**Option C:** ACE inhibitors are not contraindicated in patients with a history of myocardial infarction. **Incorrect**, as ACE inhibitors have been shown to reduce mortality and morbidity in patients with a history of myocardial infarction.

**Clinical Pearl / High-Yield Fact**
In patients with bilateral renal artery stenosis, ACE inhibitors can lead to a decrease in blood pressure and a decrease in GFR, exacerbating renal failure. This is a critical consideration when selecting antihypertensive therapy in patients with renal disease.

**Correct Answer: C. ACE inhibitors are not contraindicated in patients with a history of myocardial infarction.**