PLEEZ HALP! The graph shows the amount of money paid when purchasing bags of candy at the zoo:

A graph is shown. The x-axis is labeled from 0 to 12 and the y-axis is labeled from 0 to 12. The four points are shown on the graph are ordered pairs 0, 0 and 1, 2 and 2, 4 and 3, 6. These points are joined by a line. The label on the x-axis is Bags of candy. The title on the y-axis is Total cost in dollars.

Write an equation to represent the relationship between the total cost (y) and the number of bags of candy (x).

y = one-half x
y = 2x
y = 3x
y = one-third x