**Core Concept**
Severe preeclampsia is a hypertensive disorder of pregnancy characterized by high blood pressure and end-organ damage, necessitating prompt treatment to prevent maternal and fetal morbidity. The management of severe preeclampsia involves antihypertensive therapy to control blood pressure and prevent complications.

**Why the Correct Answer is Right**
Labetalol is the drug of choice for severe preeclampsia due to its ability to effectively lower blood pressure while minimizing fetal risk. Labetalol is a mixed alpha and beta-blocker that works by reducing peripheral resistance and cardiac output. It has a rapid onset of action and is well-studied in pregnant women, making it a safe and effective choice for severe preeclampsia.

**Why Each Wrong Option is Incorrect**
**Option A:** Methyldopa is a centrally acting alpha-2 agonist that is commonly used in pregnancy, but it is not the first-line treatment for severe preeclampsia due to its slower onset of action and potential for fetal side effects.
**Option B:** Hydralazine is a vasodilator that is often used in pregnancy, but it is typically reserved for acute blood pressure control in severe preeclampsia and is not the preferred long-term treatment.
**Option C:** Nifedipine is a calcium channel blocker that can be used in pregnancy, but it is not the first-line treatment for severe preeclampsia due to concerns about fetal risk and the need for close monitoring.

**Clinical Pearl / High-Yield Fact**
In severe preeclampsia, the goal of antihypertensive therapy is to lower blood pressure to 160/110 mmHg or less while ensuring adequate uteroplacental perfusion to prevent fetal compromise.

**Correct Answer:** C. Labetalol is the drug of choice for severe preeclampsia due to its effectiveness and safety profile.