This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demography and family planning, Subject name: Social & Preventive Medicine
[{'content': 'Vital statistics in a population include \nSelect and explain. \nA. Sex ratio, B. Age composition, C. Bih rate, D. Dependency rate', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Population Statistics Vital Statistics Population size Bih rate, Death rate Sex ratio Natural growth rate Density of population Life expectancy at bih Depedency ratio Moality rates Feility rates Ref: Park 25th edition Pgno: 532', 'role': 'assistant'}]