The graph below shows the numbers of cups of peach juice that are mixed with different numbers of cups of lemon-lime soda to make servings of peach soda: A graph is shown. The values on the x axis are 0, 1, 2, 3, 4, 5. The values on the y axis are 0, 9, 18, 27, 36, 45. Points are shown on ordered pairs 0, 0 and 1, 9 and 2, 18 and 3, 27 and 4, 36. These points are connected by a line. The label on the x axis is Lemon lime soda in cups. The title on the y axis is Peach juice in cups.

What is the ratio of the number of cups of peach juice to the number of cups of lemon-lime soda?

a. 9:1
b. 1:36
c. 36:1
d. 1:9