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: Social & Preventive Medicine
[{'content': 'Gold standard study for Clinical research is \nSelect and explain. \nA. Randomised double-blind trial, B. Systematic meta-analysis, C. Ecological study, D. Retrospective cohort study', 'role': 'user'}, {'content': 'Answer: B \nExplanation: • Meta-analysis (Highest clinical relevance: GOLD STANDARD)\n• Systematic review\n• Cohort study\n• Case control study\n• Case series\n• Case report\n• Ideas, Editorials, Opinions\n• Animal research\n• In-vitro (test-tube) research (Lowest clinical relevance)', 'role': 'assistant'}]