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: Medicine
[{'content': 'Xerophthalmia is a public health problem if prevalence of bitot spots is \nSelect and explain. \nA. > 1%, B. >0.5%, C. > 0.01%, D. > 0.05%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Night blindness :\xa0> 1%.\nBitot spots : >0.5%.\nCorneal ulcer : >0.05%.\nCorneal xerosis : >0.01%.', 'role': 'assistant'}]