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
Prevalence of Vitamin A deficiency in a community is assessed as 
Select and explain. 
A. Night blindness-10%, B. Corneal ulcer-0.01%, C. Bitot spots-0.5%, D. Decreased serum retinol level-0.05%
C: Bitot spots-0.5%
Answer: C: Bitot spots-0.5% 
Explanation: None