This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T, Subject name: Surgery
[{'content': 'In rectal cancer, the distal clearance margin should be at least \nSelect and explain. \nA. 2 cm, B. 3cm, C. 4 cm, D. 5 cm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Tumor margin for curative resection 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 Ref: Sabiston 20th edition Pgno : 1378', 'role': 'assistant'}]