This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rectum and anal canal, Subject name: Surgery
[{'content': 'In rectal carcinoma, distal margin should be at least: \nSelect and explain. \nA. 2 cm, B. 3 cm, C. 4 cm, D. 5 cm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tumor Margin For Curative Excision In GI malignancies (stomach, small intestine, colon and proximal rectum), tumor margin for curative excision is 5 cm except: Esophagus: 10 cm Distal rectum: 2 cm', 'role': 'assistant'}]