Maggie has $32 in her money box. She plans to put $9 in her money box every month. If f(n) represents the total amount of money Maggie will have in her money box after n months, which of the following functions represents the relationship between f(n) and n?
f(n) = 9n + 32
f(n) = 32n + 9
f(n) = 41n + 9
f(n) = 9n + 41