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': 'Amount of gap required for cement in restoration is: \nSelect and explain. \nA. 10-25 microns, B. 2 microns, C. 50-100 microns, D. No gap required', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]