Which set of ordered pairs is not a function?

Diane owes $387 to her brother. if she debits her bank account $161.25 a month to pay him back, how many months will it take her to pay off the debt?

Astick 2 m long is placed vertically at point b. the top of the stick is in line with the top of a tree as seen from point a, which is 3 m from the stick and 30 m from the tree. how tall is the tree?

Which inequality statement describes the two numbers on a number line? "? 7 and a number 5 units to the right of ? 7"