**Core Concept**
Meconium peritonitis is a rare condition characterized by the leakage of meconium into the peritoneal cavity, typically in newborns. This condition is often associated with intestinal obstruction or perforation.

**Why the Correct Answer is Right**
Meconium peritonitis occurs when there is a disruption in the integrity of the intestinal wall, allowing meconium to leak into the peritoneal cavity. This can be due to various reasons such as intestinal atresia, meconium ileus, or a congenital anomaly of the intestine. The leakage of meconium into the peritoneal cavity triggers an inflammatory response, leading to the characteristic clinical presentation of meconium peritonitis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because meconium peritonitis is not typically associated with a gastrointestinal infection.
* **Option B:** This option is incorrect because meconium peritonitis is not a benign condition, but rather a serious complication that requires prompt medical attention.
* **Option C:** This option is incorrect because meconium peritonitis is not a normal variant of the peritoneal cavity, but rather a pathological condition.

**Clinical Pearl / High-Yield Fact**
Meconium peritonitis is a classic example of a condition that requires a high index of suspicion in newborns presenting with abdominal distension and vomiting. A prompt diagnosis and management of the underlying cause are crucial to prevent complications and improve outcomes.

**Correct Answer: C. Intestinal obstruction or perforation.**