**Core Concept**
The question is testing the diagnosis of a condition characterized by recurrent intestinal obstruction, a palpable abdominal mass, and diarrhea in children. This condition is often associated with a specific anatomical anomaly that affects the intestinal tract.

**Why the Correct Answer is Right**
The correct condition is Intussusception, a pathologic process where a part of the intestine folds into the adjacent part, causing obstruction and potentially leading to ischemia. Intussusception occurs due to the presence of a lead point, such as a Peyer's patch or a Meckel's diverticulum, which initiates the intussusception process. The mass per rectum is often described as a "currant jelly" stool due to the presence of blood and mucus.

**Why Each Wrong Option is Incorrect**
**Option A:** Hirschsprung's disease is characterized by a congenital absence of ganglion cells in the distal colon, leading to chronic constipation and intestinal obstruction, but it does not typically present with a palpable abdominal mass or diarrhea.

**Option B:** Meckel's diverticulum is a congenital anomaly of the small intestine that can cause gastrointestinal bleeding, but it is not typically associated with a palpable abdominal mass or recurrent obstruction.

**Option C:** Gastrointestinal stromal tumor (GIST) is a rare tumor of the gastrointestinal tract that can cause intestinal obstruction, but it is more commonly seen in adults and is not typically associated with a palpable abdominal mass in children.

**Clinical Pearl / High-Yield Fact**
The "3 Ps" of intussusception are: palpable abdominal mass, pain, and passage of blood per rectum.

**Correct Answer: C. Intussusception**