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': 'Carcinoma Anal canal: Treatment of choice is \nSelect and explain. \nA. Chemoradiation, B. Radiotherapy + chemotherapy following APR, C. Radiotherapy, D. Radiotherapy + APR', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Treatment is by chemoradiotherapy in the first instance.Major ablative surgery is required if the above fails,Uncommon tumour, which is usually a squamous cell carcinoma Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1269', 'role': 'assistant'}]