Ordered pairs in which of these formats would always represent a function?

A. (number of months since birth, age in years)

B. (height, age)

C. (age, weight)

D. (age, grade in school)

Basically, the same first number repeats with a differnet second number

A. number of months always changes so it will never repeat, ths is a function

B. you can grow shorter somehow so heights could be repeated or you could never grow

C. age always goes up, but you could be different weights in the same age so this isnt' a function

D. same as last, you could change grades in the same year

A is ansre