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': 'Film speed best for detection of incipient caries: \nSelect and explain. \nA. C, B. D, C. E, D. F', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]