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
[{'content': 'A plain X ray abdomen is performed in case of small bowel obstruction. Small bowel would be called dilated if its diameter is more than: \nSelect and explain. \nA. 2 cm, B. 3 cm, C. 4 cm, D. 5 cm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Normal bowel caliber: Small bowel- <3 cm Large bowel- <6 cm Caecum- <9 cm Thus, small bowel is called dilated if its caliber is >3 cm.', 'role': 'assistant'}]