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
Case series repo is a type of ? 
Select and explain. 
A. Analytic study, B. Experimental study, C. Observational study, D. Intervention study
C: Observational study
Answer: C: Observational study 
Explanation: Ans. is 'c' i.e., Observational study A) Observational studiesDescriptive studies : Case repos, case series.Analytic studies : Case-control (case-reference), Coho (follow-up), Ecological (correlational), Cross-sectional.B) Experimental/intervention studiesRandomized controlled trials/clinical trials.Community trials.Field trials. Animal studies.