**Core Concept**
The underlying principle in this question is the differentiation between various hypertensive disorders in pregnancy, specifically preeclampsia, chronic hypertension, gestational hypertension, and eclampsia. These conditions have distinct diagnostic criteria and implications for maternal and fetal health.

**Why the Correct Answer is Right**
Chronic hypertension is defined as hypertension that is diagnosed before 20 weeks of gestation or persists beyond 12 weeks postpartum. In this case, the patient's blood pressure readings are elevated, but she has no symptoms and a negative urinalysis for protein, which makes preeclampsia less likely. The absence of proteinuria (protein in the urine) further supports the diagnosis of chronic hypertension. Chronic hypertension can be associated with other underlying medical conditions, such as renal disease or cardiovascular disease, which may not be immediately apparent in this patient.

**Why Each Wrong Option is Incorrect**
**Option A:** Preeclampsia typically presents with new-onset hypertension after 20 weeks of gestation, accompanied by proteinuria (≥ 300 mg/24 hours or 1+ proteinuria on dipstick). This patient's presentation does not meet these criteria.
**Option C:** Eclampsia is the onset of seizures in a woman with preeclampsia. This patient has no symptoms of preeclampsia, and her blood pressure is not high enough to suggest eclampsia.
**Option D:** Gestational hypertension is defined as new-onset hypertension after 20 weeks of gestation without proteinuria. While this patient's hypertension is new, her blood pressure is high enough to suggest chronic hypertension rather than gestational hypertension.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that chronic hypertension in pregnancy can be asymptomatic, and patients may not exhibit any noticeable symptoms. A thorough medical and obstetric history, as well as a physical examination, is crucial in diagnosing chronic hypertension.

**✓ Correct Answer: B. Chronic hypeension**