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': 'WHO immunization evaluation coverage survey is normally done in what age group? \nSelect and explain. \nA. 0-12 months, B. 6-12 months, C. 12-23 months, D. 9-12 months', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., 12-23 months WHO used 30 x 7 technique (total = 210 children) for cluster sampling in which there are 30 clusters, each containing 7 childrenwho are 12 - 23 months old and are completely immunized for primary immunization (till measles vaccine at 9 month).", 'role': 'assistant'}]