单项选择题

A.体重(kg)=年龄(岁)X2+6(或7)
B.体重(kg)=年龄(岁)X2+7(或8)
C.体重(kg)=年龄(岁)X2+5(或6)
D.体重(kg)=年龄(岁)X2+8(或9)