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: Social & Preventive Medicine
[{'content': 'Denominator of dependency ratio includes population of age \nSelect and explain. \nA. >15 years + > 65 years, B. 15 - 65 years of age, C. < 65 years, D. > 65 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]