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: Social & Preventive Medicine
[{'content': 'Light index in living room is – \nSelect and explain. \nA. 8, B. 15, C. 20, D. 25', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]