This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
[{'content': 'Effective literacy rate is calculated from \nSelect and explain. \nA. Those who have completed 15 year schooling, B. Those who have completed 10 year schooling, C. Those above age of 7 years, D. Total population', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]