**Core Concept**
Alpha-blockers are a class of medications that act by blocking alpha-adrenergic receptors, leading to vasodilation and a decrease in peripheral vascular resistance. This results in a decrease in blood pressure and an increase in cardiac output.

**Why the Correct Answer is Right**
Alpha-blockers are primarily used in the management of hypertension, benign prostatic hyperplasia (BPH), and pheochromocytoma. They work by relaxing smooth muscle in blood vessels, leading to vasodilation and a decrease in blood pressure. In BPH, alpha-blockers help to relax the smooth muscle in the prostate, making it easier to urinate. In pheochromocytoma, alpha-blockers are used to manage the symptoms of excess catecholamine production.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because alpha-blockers are not primarily used in the management of asthma. Alpha-blockers are not bronchodilators and do not have a significant effect on airway smooth muscle.
**Option B:** This option is incorrect because alpha-blockers are not primarily used in the management of glaucoma. Alpha-blockers are not typically used to treat glaucoma, and other classes of medications such as beta-blockers, prostaglandin analogs, and cholinergic agonists are more commonly used.
**Option C:** This option is incorrect because alpha-blockers are not primarily used in the management of heart failure. Alpha-blockers can actually worsen heart failure in some cases by reducing blood pressure and cardiac output.

**Clinical Pearl / High-Yield Fact**
Alpha-blockers can cause a first-dose hypotension effect, which can be severe in some cases. This effect is more common in patients who are volume-depleted or who have a history of heart disease.

**Correct Answer:** A.