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: Dental
[{'content': 'The basic tools of measurement in epidemiology are \nSelect and explain. \nA. Incidence, prevalence and index, B. Morbidity, mortality and disability, C. Rates, ratios and proportions, D. Endemic, pandemic and epidemic', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]