This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Non communicable diseases, Subject name: Social & Preventive Medicine
The WHO definition for blindness is the inability of counting fingers in daylight at a minimum distance of - 
Select and explain. 
A. 3 feet, B. 6 feet, C. 3 metres, D. 6 metres
C: 3 metres
Answer: C: 3 metres 
Explanation: WHO definition blindness - inability to count fingers in day light at a distance of 3 metres or visual acuity less than 3/ 60 or its equivalent. Ref- Park&;s textbook of Preventive and social medicine 23rd edition. .