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': 'During cavity preparation, more incidence of exposure is in \nSelect and explain. \nA. Class V cavity in first premolar, B. Class II mesio occlusal cavity, C. Class II disto occlusal cavity, D. Class IV cavity', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]