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
Full bowel preparation is avoided in all, except ? 
Select and explain. 
A. Carcinoma colon, B. Hirschprung disease, C. Ulcerative colitis, D. Irritable bowel syndrome
A: Carcinoma colon
Answer: A: Carcinoma colon 
Explanation: Ans. is None or 'a' i.e., Carcinoma colon