**Core Concept:**
Interlobar pleural effusion is a condition characterized by the accumulation of fluid between the pleural layers (anterior and posterior layers of the pleura) surrounding the lungs. This fluid can impair lung expansion, leading to decreased oxygenation and ventilation. The pleural space is separated from the pleural cavity by the parietal pleura and the visceral pleura. When fluid accumulates, it is referred to as an interlobar effusion.

**Why the Correct Answer is Right:**
The correct answer, **Option C: Midline Chest X-ray**, is chosen because it provides a comprehensive view of both lungs and helps visualize the effusion's size, location, and extent. Midline chest X-rays are essential for assessing pleural effusions as they avoid any overlapping of the lungs and provide a clear view of the pleural space.

**Why Each Wrong Option is Incorrect:**
- **Option A: Right Side View:** A right side chest X-ray is limited in evaluating an interlobar effusion in the left lung as it can only visualize one lung at a time.
- **Option B: Left Side View:** Similar to right side view, a left side chest X-ray can only evaluate one lung at a time, and it is not sufficient for a comprehensive assessment of the effusion.
- **Option D: Supine View:** While supine chest X-rays are suitable for assessing pleural effusions, they provide limited information regarding the effusion's size and extent, particularly assessing the interlobar effusions.

**Clinical Pearl:**
Interlobar pleural effusions should be evaluated using a midline chest X-ray to ensure a thorough assessment of the effusion's size, location, and extent. This comprehensive view ensures that the clinician can make an accurate diagnosis and develop an appropriate treatment plan for the patient.