Social & Preventive Medicine Children surveyed in cluster sampling for coverage of national immunization programme in? A 30 clusters of 5 children B 20 clusters of 5 children C 30 clusters of 10 children D 30 clusters of 7 children 💡 Explanation Children surveyed in cluster sampling for coverage of national immunization programme in? ✓ Correct Answer: D. 30 clusters of 7 children