Analysis: Children under 5 years old, 2 ~ 12 years old: weight (kg)= age? 2+8,2 ~12 years old: height (cm)= age? 7+75, you can know that you should choose A through calculation.
. 1 ~ 9 years old simple calculation method: the number of ossification centers of wrist is about the age of children plus 1.
. 1 year-old is 46cm, 2 years old is 48cm, 5 years old is about 50cm, 15 years old is close to the adult head circumference, about 54 ~ 58 cm.