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': 'High or low fistula is ano is termed according to its internal opening present with reference to \nSelect and explain. \nA. Anal canal, B. Dentate line, C. Anorectal ring, D. Sacral promontary', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The anorectal ring marks the junction between the rectum and the anal canal. It is formed by the joining of the puborectalis muscle. the deep external sphincter, conjoined longitudinal muscle and the highest pa of the internal sphincter. The anorectal ring can be clearly felt digitally, especially on its posterior and lateral aspects. Ref: Bailey & Love&;s Sho Practice of Surgery,E25,Page-1240', 'role': 'assistant'}]