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': 'Child survival index is the percentage of children surviving till the age of - \nSelect and explain. \nA. 1 year, B. 3 years, C. 5 years, D. 15 years', 'role': 'user'}, {'content': "Answer: C \nExplanation: park's textbook of preventive and social medicine 23rd edition. *child survival index:the basic measurement of infant and child survival is the under 5 moality.A child survival rate per 1000 bih can be simply calculated by subtracting the under 5 moality rate from 1000 dividing this figures by 10 shows the percentage of those who survive to the age of 5 year.", 'role': 'assistant'}]