This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
A 15 year old child presents in the OPD with acute abdominal pain. He also gives history of blood and mucous in the stool. On P/A examination a mass is palpable. The MOST probable diagnosis in this patient is? 
Select and explain. 
A. Meckel's diveiculum, B. Volvulus, C. Intussusception, D. Hyperophic pyloric stenosis
C: Intussusception
Answer: C: Intussusception 
Explanation: A syndrome of colicky pain, passage of blood per rectum and a palpable mass (intussuscepted segment) is characteristic of intussusception. Ref: CSDT 13/e, Page 629; Bailey & Love 25/e, Page 1191.