This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small & Large Intestine, Subject name: Surgery
[{'content': "X-ray finding more suggestive of ulcerative colitis than Crohn's disease: \nSelect and explain. \nA. Rectal sparing, B. Loss of haustrations, C. Tracking of contrast within the bowel wall, D. Discontinuous lesions", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. (b) Loss of haustrationsRef: Sabiston 20th edition, Page 1342* Lead pipe appearance: Loss of haustrations* Rectal sparing is a feature of Crohn's* Skip lesions are also seen in Crohn's.", 'role': 'assistant'}]