**Core Concept**
Pregnancy-induced hypertension (PIH) is a condition characterized by the onset of **hypertension** during pregnancy, which can lead to complications for both the mother and the fetus. The condition is diagnosed based on the elevation of **blood pressure** above a certain threshold. Severe PIH is defined by even higher **blood pressure** values.

**Why the Correct Answer is Right**
In severe PIH, the **blood pressure** is significantly elevated, typically above 160/110 mmHg. This elevation is due to **vasoconstriction** and increased **peripheral resistance**, which can lead to end-organ damage. The exact mechanism involves the **endothelin** system and an imbalance in **prostacyclin** and **thromboxane** production.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the blood pressure values are not high enough to be considered severe PIH.
**Option B:** Similarly, this option does not meet the criteria for severe PIH.
**Option C:** This option also does not represent the blood pressure values seen in severe PIH.

**Clinical Pearl / High-Yield Fact**
Severe PIH is a medical emergency that requires immediate attention to prevent complications such as **eclampsia** and **stroke**. The diagnosis and management of PIH are crucial for improving maternal and fetal outcomes.

**Correct Answer:** D. ≥160/110 mmHg