This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Pubey, Subject name: Pediatrics
[{'content': 'Precocious pubey in a girl is defined as breast development before the age of? \nSelect and explain. \nA. 6 years, B. 8 years, C. 12 years, D. 10 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Precocious pubey: Precocious pubey is defined by the onset of secondary sexual characteristics before the age of 8 years in girls and 9 years in boys.', 'role': 'assistant'}]