**Core Concept**
Labetalol is a medication used to manage hypertension, particularly in pregnant women. It has a unique mechanism of action that affects both alpha and beta-adrenergic receptors.

**Why the Correct Answer is Right**
Labetalol is a non-selective beta blocker, meaning it blocks both beta-1 and beta-2 adrenergic receptors. This action results in reduced heart rate, decreased cardiac output, and vasodilation. Additionally, labetalol is an alpha-1 blocker, which causes vasodilation by relaxing smooth muscle in blood vessels. The combined effect of alpha-1 blockade and non-selective beta blockade makes labetalol an effective antihypertensive agent. The alpha-1 blockade also reduces peripheral resistance, which contributes to its blood pressure-lowering effects.

**Why Each Wrong Option is Incorrect**
**Option A:** Labetalol does not primarily act as an alpha-1 blocker; its alpha-1 blocking effects are secondary to its main mechanism of action.
**Option B:** Labetalol is not an alpha-2 blocker; it is an alpha-1 blocker, and its alpha-2 blocking effects are not clinically significant.
**Option C:** Labetalol is not a selective beta-1 blocker; it is a non-selective beta blocker that affects both beta-1 and beta-2 receptors.

**Clinical Pearl / High-Yield Fact**
Labetalol is often used in pregnancy-induced hypertension due to its safety profile and efficacy in controlling blood pressure. It is also used in patients with heart failure, as it reduces cardiac workload and peripheral resistance.

**✓ Correct Answer: D. Alpha 1 and non-selective beta blocker**