A gym membership has an application fee of $5 plus $20 per month. Which function represents the cost of a gym membership, where x is the number of months?
Question 9 options:

A)

f(x) = 20x + 5


B)

f(x) = 5(20)x

C)

f(x) = 5x + 20

D)

f(x) = 5x2 + 20