This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Nutritional Deficiencies, Subject name: Social & Preventive Medicine
[{'content': "Xerophthalmia is considered as public health problem if prevalence of bitot's spot is more than? \nSelect and explain. \nA. 0.01%, B. 0.05%, C. 0.50%, D. 1%", 'role': 'user'}, {'content': "Answer: C \nExplanation: Assessment of vitamin A deficiency: The presence of any one of the criteria should be considered as evidence of a xerophthalmia problem in the community. - Criteria Prevalence in population at risk (6 months to 6 years) Night blindness more than 1 per cent Bitot's spots more than 0.5 per cent Corneal xerosis/ corneal ulceration/ keratomalacia more than 0.01 per cent Corneal ulcer more than 0.05 per cent Serum retinol (less than 10 mcg/dl) more than 5 per cent", 'role': 'assistant'}]