This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anal Malignancy, Subject name: Surgery
[{'content': 'Margin of clearence for anal carcinoma is- \nSelect and explain. \nA. 2 cm, B. 3 cm, C. 4 cm, D. 5 cm', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., 2 cm o Wide local excision leaving a margin of at least 2.5 cm of tissue all round with block dissection of the inguinal nodes; If they' are involved.", 'role': 'assistant'}]