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: Radiology
[{'content': 'Safest light used in darkroom in a X-ray depament is: \nSelect and explain. \nA. Dull white, B. Blue, C. Green, D. Red', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. Red', 'role': 'assistant'}]