Answer: D. The cost increases $1.25 for each additional song that is downloaded
Step-by-step explanation:
Rate of change for every function is given by :-
[tex]\text{Rate of change}=\dfrac{\text{Change in dependent variable}}{\text{Change in independent variable}}[/tex]
Here, Independent variable= number of songs
Dependent variable = cost
From the given table , it can be seen that the rate of change of cost per number of songs is 1.25 :-
[tex][\dfrac{1.25-0}{1-0}=\dfrac{1.25}{1}=1.25][/tex]
Since it is positive.
It means that "The cost increases $1.25 for each additional song that is downloaded
"