This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Inflammatory bowel disease, Subject name: Surgery
[{'content': "String sign of Kantor seen in: \nSelect and explain. \nA. Crohn's disease, B. Ulcerative colitis, C. Both of the above, D. None of the above", 'role': 'user'}, {'content': "Answer: A \nExplanation: Named features of Crohn's Disease :- Hose Pipe appearance Cobble-stone appearance Halo sign on CT String sign of Kantor Raspberry/ rosethorn appearance", 'role': 'assistant'}]