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
Hirschsprung's disease involves which region of intestine: March 2005 
Select and explain. 
A. Colon, B. Rectum, C. Rectosigmoid pa, D. Terminal ileum
C: Rectosigmoid pa
Answer: C: Rectosigmoid pa 
Explanation: Ans. C: Rectosigmoid pa