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
Carcinoma Anal canal: Treatment of choice is 
Select and explain. 
A. Chemoradiation, B. Radiotherapy + chemotherapy following APR, C. Radiotherapy, D. Radiotherapy + APR
A: Chemoradiation
Answer: A: Chemoradiation 
Explanation: 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