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: Anatomy
[{'content': 'Anal valve is found in which pa of anal canal ? \nSelect and explain. \nA. Upper, B. Middle, C. Lower, D. At anus', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Upper", 'role': 'assistant'}]