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: Dental
All of the following are random sampling methods except 
Select and explain. 
A. Quota sampling, B. Simple random sampling, C. Stratified sampling, D. Cluster sampling
A: Quota sampling
Answer: A: Quota sampling 
Explanation: Quota Sampling

Population is first segmented into mutually exclusive sub-groups (quotas), just as in stratified sampling; then judgment is used to select the units from each group non-randomly
Is a type of convenience sampling.