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': 'In epidemic, 1st step is? \nSelect and explain. \nA. Verification of diagnosis, B. Isolation, C. Immunization, D. Notification', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The steps in epidemic investigation are :\n\nVerification of diagnosis\nConfirmation of the existence of epidemic\nDefining the population at risk\nObtaining a map of the area\nCounting the population\nRapid search for all cases & their characteristics\nMedical survey\nEpidemiological case sheet\nSearching for more cases\nData analysis\nFormulation of hypothesis\nEvaluation of ecological factors\nFurther investigation of population at risk\nWriting the report', 'role': 'assistant'}]