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: Forensic Medicine
[{'content': 'Blackening and tattooing of skin and clothing can be best demonstrated by - \nSelect and explain. \nA. Luminol spray, B. Infared photography, C. Ultraviolet light, D. Magnifying lens', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]