Your friend has $80 when he goes to the fair. he spends $4 to enter the fair and $12 on food. rides at the fair cost $1.25 per ride. which function can be used to determine how much money he has left over after x rides?

a) f(x) = 1.25x + 64

b) f(x) = -16x + $80

c) f(x) = -1.25x + 64

d) f(x) = -1.25x - 64