This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concept of health and disease, Subject name: Social & Preventive Medicine
[{'content': 'The impoance of defining "population at risk" in an epidemic is \nSelect and explain. \nA. Conduct survey, B. Search for deaths, C. Calculate attack rates, D. Prepare case sheet', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The population census will help in computing the much-needed attack rates in various groups and subgroups of the population.Without an appropriate denominator of &;&;population at risk,&; attack rates cannot be calculated.Ref: Park 23rd edition pg: 130', 'role': 'assistant'}]