**Core Concept**
Labetalol and methyldopa are preferred antihypertensive medications in pregnancy due to their safety profile and effectiveness in managing hypertension without causing significant fetal harm.

**Why the Correct Answer is Right**
Methyldopa acts centrally to decrease sympathetic outflow, thereby reducing peripheral vascular resistance and blood pressure. Labetalol, a mixed alpha/beta-blocker, also decreases peripheral resistance and cardiac output, making it an effective choice for managing hypertension in pregnancy. Both medications have a long history of safe use in pregnant women and are recommended as first-line treatments by various obstetric guidelines.

**Why Each Wrong Option is Incorrect**
**Option A:** Nifedipine is a calcium channel blocker that can cause fetal hypotension and bradycardia, making it a less favorable choice in pregnancy.
**Option B:** Hydralazine is a vasodilator that can cause maternal and fetal hypotension, and is typically reserved for acute management of severe hypertension in pregnancy.
**Option C:** ACE inhibitors are contraindicated in pregnancy due to the risk of fetal renal damage and oligohydramnios.

**Clinical Pearl / High-Yield Fact**
Methyldopa and labetalol are often used in combination to manage severe hypertension in pregnancy, as they have complementary mechanisms of action and can be effective in reducing blood pressure without causing significant fetal harm.

**Correct Answer: C. Methyldopa**