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': 'What is the duration of "new families"? \nSelect and explain. \nA. < 2 years, B. < 5 years, C. < 10 years, D. < 12 years', 'role': 'user'}, {'content': 'Answer: C \nExplanation: New family is a term applied to those under 10 years duration and consists of parents and children. Ref: Park 21st edition page: 633.', 'role': 'assistant'}]