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
[{'content': 'High or low fistula in ano are divided by which of the following \nSelect and explain. \nA. Anorectal ring, B. Anal canal, C. External anal spincter, D. Dentate line', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Anorectal ring is formed by internal anal spincter, external anal spincter and puborectalis muscle.', 'role': 'assistant'}]