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: Pathology
[{'content': 'Pipe stem appearance in barium enema is seen \nSelect and explain. \nA. Crohns disease, B. Ulcerative colitis, C. Schistosomiasis, D. Carcinoma colon', 'role': 'user'}, {'content': 'Answer: B \nExplanation: In UC, Transverse colon and left colon may show pipestem appearance on barium enema.', 'role': 'assistant'}]