This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Anal carcinoma is most commonly carcinoma of type 
Select and explain. 
A. Adeno carcinoma, B. Epidermoid, C. Mixed, D. None of the above
B: Epidermoid
Answer: B: Epidermoid 
Explanation: Epidermoid carcinoma of the anus includes squamous cell ca, cloacogenic ca, transitional ca & basaloid ca. The clinical behavior and natural history of these tumors is similar.