This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anal Fissures, Subject name: Surgery
[{'content': 'A Sentinel pile indicates \nSelect and explain. \nA. Internal hemorrhoids, B. Pilonidal sinus, C. Fissure in ano, D. Fistula in ano', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c (Fissure in ano) (Ref. Bailey and Love Surgery 26th/1250; Ref. Q. 216 of MH-2007).SENTINEL PILE- This misnomer is given to a skin tag marking--and often containing within it--the distal end of an anal fissure, found usually in the posterior midline.', 'role': 'assistant'}]