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
High or low fistula in ano is termed according to its internal opening present with reference to 
Select and explain. 
A. Anal canal, B. Dentate line, C. Anorectal ring, D. Sacral promontory
C: Anorectal ring
Answer: C: Anorectal ring 
Explanation: Ans. is 'c' i.e. Anorectal ring