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
[{'content': 'WHO definition of blindness, Visual acuity - \nSelect and explain. \nA. <6/60, B. < 3/60, C. <6/18, D. < 6/9', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is \'b\' i.e., < 3/60 o WHO defines blindness as "Visual acuity of < 3/60 in better eye with best possible correction".Categories of visual impairmentCategories of visual impairmentVisual acuityMaximum less thanMinimum equal to or better thanLow vision1. 6/182. 6/606/603/60Blindness3. 3/60 (finger counting at 3 metres)4. 1/60 (finger counting at 1 metre)5. No light perception1/60 (finger counting at 1 metres) light perception', 'role': 'assistant'}]