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
In MCH programme the sampling is done by which method – 
Select and explain. 
A. Systemic, B. Stratified, C. Group, D. Cluster–30
D: Cluster–30
Answer: D: Cluster–30 
Explanation: None