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: Radiology
[{'content': "Fleishner sign is characteristic of \nSelect and explain. \nA. Ulcerative colitis, B. Crohn's disease, C. Ischaemic colitis, D. Ileocecal tb", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Fleshner sign - Wide gaping of ileocecal value with narrowing of terminal ileum characteristic of Ileocecal tb.', 'role': 'assistant'}]