This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
All of the following are random sampling methods except- 
Select and explain. 
A. Simple random, B. Cluster sampling, C. Stratified random, D. Quota sampling
D: Quota sampling
Answer: D: Quota sampling 
Explanation: <p> Quota sampling. Reference:Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:850. <\p>