**Core Concept**
The question tests understanding of the mechanisms of action of antihypertensive drugs, which are used to treat high blood pressure. These drugs can act through various pathways, including blocking certain receptors or enzymes. **Antihypertensive** drugs are crucial in managing **hypertension**, a significant risk factor for cardiovascular diseases.

**Why the Correct Answer is Right**
To answer this question correctly, one must know the common mechanisms of action of antihypertensive drugs. Most antihypertensive drugs work by either blocking receptors (like **beta-blockers** blocking beta-adrenergic receptors or **ACE inhibitors** blocking the conversion of angiotensin I to angiotensin II), inhibiting enzymes (such as **direct renin inhibitors**), or acting on the vascular smooth muscle directly (like **calcium channel blockers**).

**Why Each Wrong Option is Incorrect**
**Option A:** This choice is incorrect because some antihypertensive drugs do indeed work by blocking alpha-adrenergic receptors, reducing vasoconstriction and thus lowering blood pressure.
**Option B:** Incorrect because beta-blockers, a class of antihypertensive drugs, act by blocking beta-adrenergic receptors, which reduces heart rate and contractility, thereby lowering blood pressure.
**Option C:** This option is also incorrect as certain antihypertensive drugs, such as ACE inhibitors and angiotensin II receptor blockers (ARBs), block the effects of angiotensin II, a potent vasoconstrictor.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that understanding the mechanism of action of antihypertensive drugs is crucial for their effective and safe use. Each class of drugs has its specific indications, contraindications, and side effects, which are directly related to how they act to lower blood pressure.

**Correct Answer: D.**