**Core Concept**
Intussusception is a medical emergency characterized by the telescoping of a segment of the intestine into another adjacent segment, leading to bowel obstruction and potentially life-threatening complications. This condition is most commonly seen in infants between 5-10 months of age.

**Why the Correct Answer is Right**
Intussusception typically presents with episodic abdominal pain, often described as colicky, which is relieved by the passage of blood-stained stools (currant jelly stool). The pain is usually colicky and may be accompanied by vomiting. The child may also exhibit signs of distress, such as drawing up of the legs and irritability. The pathogenesis of intussusception is not fully understood, but it is thought to be related to the abnormal development of the intestinal mesentery, which allows the intestine to twist and telescope into adjacent segments.

**Why Each Wrong Option is Incorrect**
**Option A:** Meckel's diverticulum is a congenital anomaly of the small intestine, but it is not typically associated with the acute presentation of intussusception. Meckel's diverticulum may cause gastrointestinal bleeding, but it usually presents with iron-deficiency anemia in older children.

**Option C:** Malrotation is a congenital anomaly of the intestine where the intestine does not rotate properly during fetal development, leading to intestinal obstruction. While malrotation can cause abdominal pain and vomiting, it is not typically associated with the characteristic relief of pain with the passage of blood-stained stools seen in intussusception.

**Option D:** Intestinal obstruction refers to a blockage of the intestine that prevents the normal flow of intestinal contents. While intestinal obstruction can cause abdominal pain and vomiting, it is a more general term and does not specifically describe the telescoping of one segment of the intestine into another, which is characteristic of intussusception.

**Clinical Pearl / High-Yield Fact**
The "currant jelly" stool, characterized by its bright red color and jelly-like consistency, is a classic sign of intussusception. This sign is due to the presence of blood and mucus in the stool, which is produced as a result of the telescoping of the intestine.

**✓ Correct Answer: B. Intussusception**