**Core Concept**
The patient's clinical presentation and laboratory findings are consistent with pulmonary fibrosis, a condition characterized by the progressive scarring of lung tissue, leading to impaired gas exchange and respiratory failure. The presence of bilateral pleural effusions and a prominent right heart border on chest radiograph further supports this diagnosis.

**Why the Correct Answer is Right**
The microscopic findings in pulmonary fibrosis are characterized by the presence of fibroblasts, myofibroblasts, and the deposition of extracellular matrix proteins, including collagen. The fibrotic process involves the activation of alveolar macrophages, which release cytokines and growth factors that promote the proliferation and differentiation of fibroblasts into myofibroblasts. These myofibroblasts produce and deposit excess collagen, leading to the scarring of lung tissue and impaired gas exchange.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it describes the microscopic findings in acute respiratory distress syndrome (ARDS), which is characterized by diffuse alveolar damage and the presence of hyaline membranes, but not typically by fibrosis.
* **Option B:** This option is incorrect because it describes the microscopic findings in tuberculosis, which is characterized by granulomatous inflammation and caseous necrosis, but not typically by fibrosis.
* **Option C:** This option is incorrect because it describes the microscopic findings in sarcoidosis, which is characterized by non-caseating granulomas, but not typically by fibrosis.

**Clinical Pearl / High-Yield Fact**
In cases of pulmonary fibrosis, the presence of a prominent right heart border on chest radiograph is a sign of cor pulmonale, a condition characterized by right ventricular hypertrophy and failure due to chronic pulmonary hypertension.

**Correct Answer:** C.