This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': 'A sunscreen ointment has a Sun-Protection-Factor (SPF) of 15.How much of UV radiation it filters out. \nSelect and explain. \nA. 15%, B. 85%, C. 93%, D. 98%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: "SPF 15" means that 1/15th of the burning radiation reaches the skin through the recommended thickness of sunscreen SPF 15 sunscreens filter out about 93% of UVB rays, while SPF 30 sunscreens filter out about 97%, SPF 50 sunscreens about 98% Ref: https://en.m.wikipedia.org/wiki/Sunscreen', 'role': 'assistant'}]