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: Unknown
[{'content': 'The appearance of the colon on a barium enema is seen in \nSelect and explain. \nA. Amoebiasis, B. Ulcerative colitis, C. Tuberculosis of the colon, D. Crohn’s involvement of the colon', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]