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
Retrospective study is - 
Select and explain. 
A. Case-control study, B. Cohort study, C. Cross-sectional study, D. RCT
A: Case-control study
Answer: A: Case-control study 
Explanation: 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).