This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sampling, Subject name: Social & Preventive Medicine
[{'content': 'In a study every fouh student is selected in a class while sampling. This is a type of:- \nSelect and explain. \nA. Simple random sampling, B. Systematic random sampling, C. Stratified random sampling, D. Cluster random sampling', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Systematic Random Sampling:- Based on sampling fraction: Every Kth unit is chosen in the population list, where K is chosen by sampling internal. Sampling interval (K) : Total no. of units in population / Total No of units in sample.', 'role': 'assistant'}]