This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Biostatistics, Subject name: Social & Preventive Medicine
[{'content': 'What is the method of sampling in which the units are picked up at regular intervals from the universe- \nSelect and explain. \nA. Simple random sampling, B. Systematic random sampling, C. Stratified random sampling, D. Snow - ball sampling', 'role': 'user'}, {'content': 'Answer: B \nExplanation: .', 'role': 'assistant'}]