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': 'The type of sampling where the individual himself introduces the other subjects of surgery is called as: \nSelect and explain. \nA. Systemic sampling, B. Snowball sampling, C. Introductory sampling, D. Successive sampling', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Snowball sampling is a technique for developing a research sample, where\xa0existing\xa0study\xa0subjects\xa0recruit\xa0future\xa0subjects\xa0from\xa0among\xa0their acquaintances.\nIt is a type of non-probability sampling.\nThis sampling technique is often used in hidden populations which are difficult for researchers to access; example, drug users or commercial sex workers.\nThus, the sample group appears to grow like a rolling snowball.\nBecause sample members are not selected from a sampling frame, snowball samples are subjected\xa0to numerous biases.', 'role': 'assistant'}]