Do these pairs of values (x and y) represent two quantities that are proportional?
x y
3 15
5 25
6 30
9 45

a) No, because none of the pairs is a simplified ratio.
b) No, because each y-value is less than the corresponding x-value. C
c) Yes, because as x increases, y increases.
d) Yes, because all of the pairs represent the same ratio.