Luke is keeping track of the total number of hours he exercises. he started the summer having already put in 15 hours, and he then exercises 7 hours each week. the function to keep track of his exercise is f(x) = 7x + 15. what do the f(x) and x represent in luke's situation? (2 points)

a) f(x) represents the total number of hours; x represents the number of weeks he exercises this summer
b) f(x) represents the total number of weeks that he has exercised; x represents the number of hours
c) f(x) represents the number of hours he exercises per day; x represents the number of weeks
d) f(x) represents the total number of hours that luke has exercised; x represents the number of weeks he exercises per day