**Core Concept**
Pleural effusion is the accumulation of excess fluid in the pleural space, which can be detected radiographically using various imaging techniques, including the lateral decubitus view. The lateral decubitus view is a specific radiographic position where the patient lies on their side, allowing the pleural fluid to collect in a dependent position and become more readily visible on the radiograph.

**Why the Correct Answer is Right**
The lateral decubitus view is sensitive for detecting small pleural effusions because it allows the fluid to accumulate in the dependent portion of the pleural space. In this position, as little as 25 ml of fluid can be detected radiographically, as it becomes visible as a meniscus sign or a blunted costophrenic angle. This is because the fluid collects in the lowermost portion of the pleural space, making it more conspicuous on the radiograph.

**Why Each Wrong Option is Incorrect**
**Option A:** 15 ml is too small an amount of fluid to be reliably detected in the lateral decubitus view, as it may not be sufficient to produce a visible meniscus sign or blunted costophrenic angle.
**Option C:** 35 ml is still within the detectable range, but not the minimum amount required for radiological detection in the lateral decubitus view.
**Option D:** 45 ml is a significant amount of fluid, but the question specifically asks for the minimum amount required for detection, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
In radiographic imaging of the chest, the lateral decubitus view is particularly useful for detecting small pleural effusions, as it allows the fluid to collect in a dependent position and become more visible on the radiograph. This is a key exam-relevant point to remember when interpreting chest radiographs.

**✓ Correct Answer: B. 25 ml**