This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiological Study, Subject name: Social & Preventive Medicine
[{'content': 'Retrospective study is - \nSelect and explain. \nA. Case-control study, B. Cohort study, C. Cross-sectional study, D. RCT', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a > b' i.e., Case-control study > Cohort study o Case-control study is a retrospective study.o Cohort study is mostly a prospective study. But retrospective cohort studies are also there (has been explained in previous sessions).", 'role': 'assistant'}]