**Core Concept**
Pregnancy-induced hypertension (PIH) is a condition characterized by new-onset hypertension in pregnant women, typically after 20 weeks of gestation. The primary goal of treatment is to control blood pressure and prevent complications such as preeclampsia and eclampsia.

**Why the Correct Answer is Right**
Labetalol is a mixed alpha/beta-adrenergic antagonist that is commonly used as a first-line treatment for PIH. Its mechanism of action involves blocking alpha-1 receptors, which causes vasodilation and reduces peripheral resistance, and blocking beta-1 receptors, which decreases cardiac output. This dual action helps to control blood pressure without significantly affecting fetal heart rate or placental blood flow.

**Why Each Wrong Option is Incorrect**
**Option A:** Methyldopa is another antihypertensive medication that can be used in pregnancy, but it is not the first-line treatment for PIH.
**Option B:** Hydralazine is a vasodilator that can be used to control acute hypertension in pregnancy, but it is not the preferred long-term treatment for PIH.
**Option C:** Nifedipine is a calcium channel blocker that can be used in pregnancy, but it is not the first-line treatment for PIH due to concerns about fetal growth restriction.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that labetalol is the preferred first-line treatment for PIH due to its dual mechanism of action and lack of significant fetal side effects.

**Correct Answer: C. Labetalol**