This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pediatrics
Precocious puberty in girls is defined by the onset of secondary sexual characteristics before the age of: 
Select and explain. 
A. 5 years, B. 7 years, C. 8 years, D. 9 years
C: 8 years
Answer: C: 8 years 
Explanation: c. 8 years(Ref: Nelson's 20/e p 2656)Precocious puberty is defined by the onset of secondary sexual characteristics before the age of 8 yr in girls and 9 yr in boys.