This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pediatrics
A 6 month child woke up in night crying with abdominal pain which got relieved on passing red stools. What is the diagnosis? 
Select and explain. 
A. Meckel's diveiculum, B. Intussusception, C. Malrotation, D. Intestinal obstruction
B: Intussusception
Answer: B: Intussusception 
Explanation: Intussusception Mostly seen in 6-11 months of age intermittent colicky abdominal pain,vomiting,bloody mucus(current jelly)the classic triad is encountered only in 20-40%cases history of recent change of milk formula,upper respiratory tract infections,or vaccination Manifest as crying episodes A sausage shaped mass may be palpable in the right quadrant,right iliac fossa is usually empty Ref : ESSENTIAL PEDIATRICS,O.P.GHAI, PG NO:259,7th edition