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': 'A thicker rubber dam is recommended for……………cavity \nSelect and explain. \nA. Class 1, B. Class 2, C. Class 4, D. Class 5', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A thicker dam is more effective in retracting tissue and more resistant to tearing; it is especially recommended for isolating Class V lesions in conjunction with a cervical retainer', 'role': 'assistant'}]