**Core Concept**
The pathogenesis of the pleural effusion in this patient is likely due to an exudative process, characterized by the presence of high protein levels, high LDH levels, and a low glucose level in the pleural fluid, compared to serum. This indicates an inflammatory or infectious process affecting the pleura.

**Why the Correct Answer is Right**
The presence of high protein levels (4.0 g/dL) and LDH levels (400 U/L) in the pleural fluid, compared to serum, suggests an exudative process. The low glucose level (75 mg/dL) in the pleural fluid, despite a normal serum glucose level, also supports this diagnosis. This pattern is consistent with a parapneumonic effusion, which is an inflammatory response to a bacterial infection in the lung, leading to the accumulation of fluid in the pleural space.

**Why Each Wrong Option is Incorrect**

**Option A:** Empyema is a complication of a parapneumonic effusion that becomes infected and is characterized by a high cell count (>50,000 cells/mm3), high LDH levels, and low glucose levels. However, the cell count in this case is relatively low (1110/mm3), making empyema less likely.

**Option B:** Transudative pleural effusions are characterized by low protein levels (<3 g/dL) and low LDH levels, which is not consistent with the patient's pleural fluid profile. **Option C:** Chylothorax is a condition where lymphatic fluid accumulates in the pleural space, typically characterized by a high triglyceride level in the pleural fluid. There is no information provided about triglyceride levels in this case. **Option D:** Hemothorax is characterized by the presence of blood in the pleural space, which is not suggested by the pleural fluid characteristics in this case. **Clinical Pearl / High-Yield Fact** In patients with a pleural effusion, a low glucose level in the pleural fluid, despite a normal serum glucose level, is a red flag for an exudative process, such as a parapneumonic effusion. **Correct Answer: C.**