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': 'Sampling method used in assessing immunization status of children under immunization programme is \nSelect and explain. \nA. Systemic sampleing, B. Stratified sampling, C. Group sampling, D. Cluster sampling', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Cluster sampling o In the Expanded programme on Immunization (EPI) cluster technique, a simplified cluster sampling method is used. It is based on ranodm selection of 210 children who are 12-23 months of age. These patients are selected in 30 clusters of 7 children each to estimate immunization coverage levels.", 'role': 'assistant'}]