5) Tony rents a bicycle in the park. He has to pay a fixed amount of Php 10 and an additional cost of Php 15 per hour or a fraction of an hour, thereafter. What is the correct mathematical model of the situation?

a) f(x) = 15x + 10
b) f(x) = 15x - 10
c) f(x) = 10x + 15
d) y = 10x - 15 ​