**Core Concept**
The Double Bubble sign is a radiological finding associated with intestinal obstruction, particularly in the context of duodenal atresia or stenosis. It refers to the presence of two distinct air-filled structures in the upper abdominal region on an erect chest radiograph or ultrasound.

**Why the Correct Answer is Right**
The Double Bubble sign is due to the accumulation of air in the stomach and the proximal duodenum, which are separated from the rest of the intestines by the obstruction. This leads to the formation of two distinct air bubbles, one in the stomach and another in the proximal duodenum. The air in the stomach and duodenum is visible on radiographs due to the gas-filled nature of these structures.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the Double Bubble sign is not typically associated with gastric outlet obstruction, which would more likely present with a single air-filled structure in the stomach.
* **Option B:** This option is incorrect because the Double Bubble sign is not a characteristic finding in small bowel obstruction, which would typically present with multiple air-filled loops of intestine on imaging.
* **Option C:** This option is incorrect because the Double Bubble sign is not a specific finding in pancreatic pathology, although pancreatic diseases can cause intestinal obstruction.

**Clinical Pearl / High-Yield Fact**
The Double Bubble sign is a classic radiological finding in duodenal atresia or stenosis, which is a congenital anomaly that can present with vomiting, abdominal distension, and failure to pass meconium in newborns.

**Correct Answer: D. Duodenal atresia or stenosis**