This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NCDs: CHD, HTN, DM, RF, Cancers, Obesity, Blindness, Subject name: Social & Preventive Medicine
[{'content': 'According to WHO, blindness there is inability to count fingers at a distance of: \nSelect and explain. \nA. 1 meters, B. 2 meters, C. 3 metres, D. 6 metres', 'role': 'user'}, {'content': "Answer: C \nExplanation: WHO defines blindness as 'visual acuity of <3/60 better eye with best possible correction' National programme for control of blindness India defines Blindness as 'visual acuity of <3/60 in better eye with best possible correction' WHO categories of Visual Impairment: Low vision <6/18 - 6/60 Economic blindness <6/60 - 3/60 - work vision Social blindness <3/60 - 1/60 - walk vision Manifest blindness < 1/60 - Perception of Light + Absolute blindness Perception of Light -ve, unspecified causes", 'role': 'assistant'}]