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': 'Picking every 5th or 10th unit at regular intervals is: \nSelect and explain. \nA. Random sampling, B. Systematic sampling, C. Stratified sampling, D. Quota sampling', 'role': 'user'}, {'content': 'Answer: B \nExplanation: A systematic sample is obtained by selecting one unit at random and then selecting additional units at evenly spaced interval till the sample of required size has been achieved.', 'role': 'assistant'}]