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': 'Which is true of ulcerative colitis: \nSelect and explain. \nA. String sign of Kantor positive, B. Skip lesions are seen, C. Rectum is always involved, D. Fistulas are common', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (c) Rectum is always involved* In ulcerative colitis rectum is always involved.* In ulcerative colitis least involved area: Anus', 'role': 'assistant'}]