This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Intestinal Obstruction, Subject name: Surgery
A 10-month-old boy has recently been weaned and placed on solid food. He develops colicky abdominal pain with vomiting. Examination of the abdomen shows emptiness in the right iliac fossa and a mass in the epigastrium. Intussusception is suspected. Following adequate hydration, this condition should be treated by which of the following? 
Select and explain. 
A. Laxatives, B. Gastrojejunostomy, C. Laparotomy and manual reduction, D. Radiologic reduction by barium with measured pressure control of column of barium
D: Radiologic reduction by barium with measured pressure control of column of barium
Answer: D: Radiologic reduction by barium with measured pressure control of column of barium 
Explanation: Treatment in infants is by controlled radiologic reduction initially, with surgery reserved for cases in which ischemia is expected or reduction is unsuccessful. The leading part of the intussusception is the apex. The outer sheath is the intussuscipiens, which receives the inner intussusceptum. The outer intussuscipiens elicits peristalsis, which forces the intussusceptum to extend distally.