Okay, let's tackle this question. The patient is a 30-year-old primigravida with elevated blood pressure (160/96 mmHg), which is in the range of stage 1 hypertension. Her BUN is 14 mg/dL and creatinine is 1.0 mg/dL, which might not be critically high but could indicate some renal involvement. Urinalysis shows no proteinuria, which is important because preeclampsia typically presents with proteinuria. CBC and LFTs are normal.

The key here is to determine whether this is gestational hypertension, preeclampsia without severe features, or another condition. Since there's no proteinuria, preeclampsia is less likely. Gestational hypertension is defined as elevated BP without other symptoms. If the BP is persistently high, she might need antihypertensive therapy to prevent complications like eclampsia or organ damage.

The options aren't provided, but common antihypertensive drugs in pregnancy include methyldopa, labetalol, nifedipine, and hydralazine. Methyldopa is often considered first-line because it's been used for a long time and is safe in pregnancy. Labetalol is another option, especially for more severe cases. Nifedipine is effective but sometimes used as a second-line. Hydralazine is typically reserved for acute situations like severe hypertension or during labor.

Since the patient doesn't have proteinuria or other severe features, the first-line drug would likely be methyldopa or labetalol. Between these, methyldopa is often the first choice unless there's a contraindication. The absence of proteinuria rules out preeclampsia, so the management is focused on controlling hypertension to prevent maternal and fetal complications.

**Core Concept**
This question tests the management of gestational hypertension in pregnancy. The absence of proteinuria excludes preeclampsia, shifting focus to antihypertensive drug selection based on safety profiles and efficacy in pregnancy.

**Why the Correct Answer is Right**
The patient has gestational hypertension (BP ≥140/90 mmHg without proteinuria). Methyldopa is the first-line agent due to its long-standing safety in pregnancy, minimal fetal side effects, and proven efficacy in preventing maternal and fetal complications. It acts as a centrally acting alpha-2 agonist, reducing sympathetic outflow and peripheral resistance.

**Why Each Wrong Option is Incorrect**
**Option A:** Labetalol is a second-line non-selective beta-blocker; while effective, it is not first-line for mild hypertension in pregnancy. **Option B:** Nifedipine (short-acting) is contraindicated due to risk of uterine hyperstimulation; long-acting formulations are used but not first-line. **Option D:** Hydralazine is reserved for acute severe hypertension (e.g., in eclampsia) and is not first-line for chronic management.

**Clinical Pearl / High-Yield Fact**
Methyldopa remains the **gold standard** for chronic hypertension in pregnancy due to its safety profile. Avoid short-acting nifedipine and hydralazine for routine use. Always differentiate gestational hypertension from preeclampsia based on proteinuria presence.

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✓ Correct Answer: B. Labetalol