**Core Concept**
Gastric outlet obstruction (GOO) refers to a mechanical or functional obstruction of the gastric outlet, which is the region between the stomach and the duodenum, where gastric contents empty into the small intestine. This condition can lead to severe symptoms, including nausea, vomiting, abdominal pain, and weight loss.

**Why the Correct Answer is Right**
The correct answer will be the statement that does not accurately describe a characteristic of gastric outlet obstruction. In GOO, the gastric outlet is narrowed or blocked, which can lead to gastric distension, increased intragastric pressure, and eventually, vomiting. The vomiting in GOO is often bilious due to the obstruction's location, which is close to the pylorus, the gatekeeper of gastric contents into the duodenum.

**Why Each Wrong Option is Incorrect**
**Option A:** Gastric outlet obstruction can present with abdominal pain, which is a common symptom. Therefore, this statement is true and not the correct answer.
**Option B:** Vomiting is a hallmark symptom of GOO, often bilious, making this statement true and not the correct answer.
**Option C:** Gastric distension is a consequence of GOO, leading to increased intragastric pressure, so this statement is true and not the correct answer.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the vomiting in gastric outlet obstruction is often bilious due to the obstruction's location near the pylorus, distinguishing it from other causes of vomiting.

**Correct Answer: D**