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
[{'content': 'All of the following are random sampling methods except \nSelect and explain. \nA. Quota sampling, B. Simple random sampling, C. Stratified sampling, D. Cluster sampling', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Quota Sampling\n\nPopulation is first segmented into mutually exclusive sub-groups (quotas), just\xa0as in stratified sampling; then judgment is used to select the units from each\xa0group non-randomly\nIs a type of convenience sampling.', 'role': 'assistant'}]