**Core Concept**
Pre-capillary pulmonary hypertension refers to a condition where the pulmonary artery pressure is elevated without any significant increase in the pulmonary vascular resistance. This is often seen in conditions such as idiopathic pulmonary arterial hypertension, where the small pulmonary arteries are narrowed or constricted, leading to increased resistance to blood flow.

**Why the Correct Answer is Right**
Pre-capillary pulmonary hypertension is characterized by an elevated mean pulmonary artery pressure (mPAP) above 25 mmHg at rest, with a pulmonary capillary wedge pressure (PCWP) ≤ 15 mmHg. This distinction is crucial as it indicates that the elevated pressure is not due to left heart disease or fluid overload, but rather due to primary pulmonary vascular disease. The pulmonary vascular resistance (PVR) is also elevated, indicating that the small pulmonary arteries are constricted or narrowed.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the criteria for pre-capillary pulmonary hypertension. Without the distinction between elevated mPAP and PCWP, it is difficult to diagnose pre-capillary pulmonary hypertension.
**Option B:** This option is incorrect as it implies that pre-capillary pulmonary hypertension is characterized by a normal pulmonary vascular resistance. However, in pre-capillary pulmonary hypertension, the PVR is actually elevated.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of pre-capillary pulmonary hypertension is the presence of right ventricular hypertrophy, which can be detected on echocardiography. This is due to the increased pressure and workload on the right ventricle, which adapts by thickening the ventricular walls.

**Correct Answer:** C.