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': 'What fraction of life do we spend chewing with primary teeth \nSelect and explain. \nA. 5%, B. 6%, C. 7%, D. 8%', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Considering average age which a human being lives as 70 years, only 6% of our life span uses primary teeth.', 'role': 'assistant'}]