Which of the Following Statements About Menarche Is Correct

Which of the following statements about menarche is correct?

A) Among girls in industrialized countries,menarche occurs,on average,between the ages of 8 and 10.
B) Menarche typically occurs two years after the beginning of indicators such as changes in the breast and pubic hair.
C) Only 50% of girls experience menarche between the ages of 11 and 15.
D) In industrialized countries,the average age of menarche has remained fairly stable for more than 100 years.