**Core Concept**
Primary pulmonary hypertension is a condition characterized by elevated pulmonary artery pressure in the absence of any identifiable cause, leading to right ventricular failure and potential complications. The ECG findings in primary pulmonary hypertension can be indicative of the underlying pathophysiology.

**Why the Correct Answer is Right**
Primary pulmonary hypertension often presents with right ventricular hypertrophy (RVH) on ECG, which is a result of the increased workload on the right ventricle due to elevated pulmonary pressures. This RVH can manifest as a tall R wave in the right precordial leads (V1-V3), a right axis deviation, and possibly a P pulmonale (prolonged PR interval). Additionally, the ECG may show signs of right atrial enlargement, such as a P wave greater than 2.5 mm in height.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
When interpreting ECGs in patients with suspected primary pulmonary hypertension, it is essential to look for signs of right ventricular hypertrophy and right atrial enlargement, as these findings can be indicative of the underlying pathophysiology.

**Correct Answer:**
Please provide the remaining options for the correct explanation.