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: Surgery
[{'content': 'Tenesmus occurs in lesions of - \nSelect and explain. \nA. Ileum, B. Right side of colon, C. Descending colon, D. Sigmoid colon', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Sigmoid colon", 'role': 'assistant'}]