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: Dental
[{'content': 'The rubber dam is approximately placed in \nSelect and explain. \nA. 3-5 min, B. 5-7 min, C. 10 min, D. 10-12 min', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]