This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Analytical Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Relative risk is calculated in? \nSelect and explain. \nA. Cross sectional study, B. Cohort study, C. Case control study, D. None', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Cohort study CharacteristicsCohort StudyCase control StudyCross Sectional StudyDesignProspectiveRetrospectiveOne point in timeIncidenceEstimatedNot estimatedNot estimatedPrevalenceNot estimatedNot estimatedEstimatedCalculationso Incidence rateso Relative risko Attributable risko Odds ratio", 'role': 'assistant'}]