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: Unknown
According to WHO leprosy is a public health problem if prevalence is more than: 
Select and explain. 
A. 0.10%, B. 0.01%, C. 0.50%, D. 1%
B: 0.01%
Answer: B: 0.01% 
Explanation: At the end 2000, leprosy was a public health problem in 10 countries (prevalence rate > 1/10,000), mainly in Africa, Asia and Latin America. Thus to call it a public health problem prevalence per 10,000 should be more than 1 and per 100 should be > 0.01.