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: Ophthalmology
WHO definition of blindness is a visual acuity in the better eye equal to or less than: 
Select and explain. 
A. Mar-60, B. Apr-60, C. May-60, D. Jun-60
B: Apr-60
Answer: B: Apr-60 
Explanation: Ans. 4/60