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': 'Enamel infarctions can be detected by \nSelect and explain. \nA. Direct illumination with visible light, B. Ultraviolet light source, C. Magnetic resonance imaging, D. Fibre optic light source', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]