**Core Concept**
Gastrointestinal obstruction can be evaluated using endoscopy, which allows for direct visualization of the **gastrointestinal tract**. This method is useful for diagnosing and sometimes treating obstructions caused by various factors. Endoscopy can help identify the location and nature of the obstruction.

**Why the Correct Answer is Right**
Since the correct answer is not provided, let's discuss the general use of endoscopy in gastrointestinal obstruction. Endoscopy is beneficial for evaluating obstructions in the upper gastrointestinal tract, such as the **esophagus**, **stomach**, and **duodenum**. It can help diagnose conditions like **esophageal strictures**, **gastric ulcers**, and **duodenal obstruction**.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be incorrect if it involves a condition where endoscopy is commonly used, such as **esophageal obstruction**.
**Option B:** Similarly, this option could be incorrect if it involves a condition like **gastric outlet obstruction**, where endoscopy is useful.
**Option C:** This option might be incorrect if it involves a condition where endoscopy is used, such as **small bowel obstruction** due to a **stricture**.
**Option D:** Without the correct answer, it's challenging to provide a specific explanation, but if this option involves a condition where endoscopy is not typically used, such as a **lower gastrointestinal obstruction** due to **intussusception**, it could be the correct answer.

**Clinical Pearl / High-Yield Fact**
Endoscopy is a valuable tool for evaluating gastrointestinal obstruction, especially in the upper gastrointestinal tract. However, its use may be limited in certain cases, such as **complete obstruction** or **lower gastrointestinal obstruction**.

**Correct Answer:** D. Complete intestinal obstruction