**Core Concept**
The patient is presenting with a complication of tuberculosis (TB) treatment, specifically the development of a parapneumonic effusion or fibrosing pleurisy, leading to restrictive lung disease and possibly cardiac involvement.

**Why the Correct Answer is Right**
The patient initially presented with lymphocyte-predominant pleural effusion and elevated adenosine deaminase (ADA) levels, consistent with tuberculous pleuritis. However, after starting anti-tubercular therapy (ATT), the patient develops progressive breathlessness, generalized body swelling, and raised jugular venous pressure (JVP), indicating fluid overload and possible cardiac involvement. The pleural fluid has transitioned to a transudate, suggesting a shift from a lymphocytic to a hydrostatic fluid accumulation. This pattern is suggestive of constrictive pericarditis, a known but rare complication of TB treatment, particularly in young women.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not account for the change in pleural fluid characteristics from lymphocyte-predominant to transudative.

**Option B:** This option is incorrect as it does not explain the development of cardiac symptoms and fluid overload.

**Option C:** This option is incorrect as it does not account for the patient's response to ATT and the transition of pleural fluid characteristics.

**Clinical Pearl / High-Yield Fact**
Constrictive pericarditis is a rare but serious complication of TB treatment, particularly in young women, and requires prompt recognition and management to prevent further cardiac complications.

**Correct Answer:** C. Constrictive pericarditis.