The skating rink charges $0.75 to rent skates and $1.25 per hour to skate. Which equation can be used to find the number of hours (h) someone skated if he or she was charged
$4.50?

a) 0.75 + 1.25 = 4.50
b) h(0.75 + 1.25) = 4.50
c) 0.75 + 1.25h = 4.50
d) 0.75h + 1.25 = 4.50