**Core Concept**
Pulmonary embolism (PE) is a life-threatening condition caused by a blockage in one of the pulmonary arteries, typically resulting from a dislodged thrombus (blood clot) from the deep veins of the legs or other parts of the body. The severity and outcome of PE depend on the size of the embolus and the presence of underlying cardiovascular disease.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology and clinical presentation of PE. When a pulmonary embolus occurs, it can lead to a sudden increase in pulmonary artery pressure, which can cause a reflexive decrease in cardiac output. This can result in symptoms such as chest pain, shortness of breath, and decreased oxygen saturation. The correct answer is likely related to the clinical consequences of PE on the cardiovascular system.

**Why Each Wrong Option is Incorrect**
**Option A:** This option may be incorrect because it does not accurately describe the pathophysiology of PE. While PE can cause hypoxemia, it is not the primary consequence of the embolus.

**Option B:** This option may be incorrect because it does not accurately describe the clinical presentation of PE. While chest pain is a common symptom of PE, it is not the only symptom, and the correct answer should be more specific.

**Option C:** This option may be incorrect because it does not accurately describe the consequences of PE on the cardiovascular system. While PE can cause a decrease in cardiac output, it is not the only consequence, and the correct answer should be more specific.

**Option D:** This option may be incorrect because it does not accurately describe the pathophysiology of PE. While PE can cause a decrease in arterial oxygen saturation, it is not the primary consequence of the embolus.

**Clinical Pearl / High-Yield Fact**
A key clinical correlation to remember is that patients with PE often present with a classic symptom complex known as the "Wells' criteria," which includes symptoms such as sudden onset of dyspnea, pleuritic chest pain, and hemoptysis. However, the most reliable clinical sign of PE is a low pre-test probability of pulmonary embolism combined with a high D-dimer level and a positive CT pulmonary angiogram.

**Correct Answer:** C.