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: Unknown
[{'content': 'Best study is - \nSelect and explain. \nA. Case-control study, B. Cohort study, C. Meta-analysis, D. RCT', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans-C Meta-analysiso Here are the different epidemiological studies with decreasing order of accuracy to test the association between risk factor and disease : -1. Systematic review and meta-analysis -->> Overall most reliable2. Randomized controlled trials (controlled clinical trails) - Most reliable individual study.3. Retrospective (Non-concurrent/historic) Cohort study.4. Prospective (concurrent) Cohort study.5. Case control study6. Cross-sectional study7. Ecological study', 'role': 'assistant'}]