**Core Concept**
A sudden onset of cough followed by increasing dyspnea is characteristic of an acute respiratory condition that leads to pulmonary edema, a condition where fluid accumulates in the lungs due to increased pressure in the pulmonary capillaries.

**Why the Correct Answer is Right**
The condition is typically caused by a severe heart failure, which increases the pressure in the pulmonary veins and capillaries, leading to fluid leakage into the alveoli. This is often seen in conditions like acute myocardial infarction (MI), where the heart muscle is damaged, leading to a decrease in cardiac output and increased pulmonary congestion. The increased pressure in the pulmonary capillaries leads to fluid accumulation, causing pulmonary edema.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a distractor related to a different respiratory condition, such as asthma or chronic obstructive pulmonary disease (COPD), which can also cause cough and dyspnea but do not typically present with sudden onset and increasing severity due to pulmonary edema.

**Option B:** This option might be a distractor related to a condition like pneumonia or bronchitis, which can cause cough and dyspnea but do not typically present with sudden onset and increasing severity due to pulmonary edema.

**Option C:** This option might be a distractor related to a condition like pleural effusion or pneumothorax, which can cause dyspnea but do not typically present with sudden onset and increasing severity due to pulmonary edema.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that in cases of acute dyspnea, especially in the context of a sudden onset of cough, one should suspect a cardiac cause, such as acute MI, which can lead to pulmonary edema. This is a classic clinical correlation that can help in making an accurate diagnosis.

**Correct Answer:** C. Pneumonia