**Core Concept**
Cor pulmonale refers to the alteration of the structure and function of the right ventricle of the heart due to a primary disorder of the respiratory system. This condition is characterized by pulmonary hypertension, leading to right ventricular failure and ultimately, cor pulmonale.

**Why the Correct Answer is Right**
The correct answer, Chronic Obstructive Pulmonary Disease (COPD), is a common cause of cor pulmonale. This is due to the progressive destruction of lung tissue and airways, leading to increased resistance to blood flow through the pulmonary vasculature. As a result, the right ventricle must work harder to pump blood through the lungs, eventually leading to right ventricular hypertrophy and failure. The chronic hypoxia and hypercapnia associated with COPD also contribute to pulmonary vasoconstriction and increased pulmonary vascular resistance.

**Why Each Wrong Option is Incorrect**
* **Option A:** Asthma is a chronic inflammatory disease of the airways, but it typically does not progress to cor pulmonale unless there is severe, uncontrolled disease or associated conditions such as chronic pulmonary embolism.
* **Option B:** Interstitial lung disease (ILD) can cause pulmonary hypertension, but it is less common than COPD as a cause of cor pulmonale. ILD typically presents with a more gradual decline in lung function.
* **Option D:** Pneumonia is an acute infection of the lung, and while it can cause acute pulmonary hypertension, it is unlikely to progress to cor pulmonale unless there is underlying chronic lung disease.

**Clinical Pearl / High-Yield Fact**
COPD is a leading cause of cor pulmonale, and the risk is increased in patients with chronic hypoxemia and hypercapnia. Early recognition and management of COPD can help prevent the development of cor pulmonale.

**Correct Answer:** C. Chronic Obstructive Pulmonary Disease (COPD)