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 9. The y-axis is labeled from 0 to 10. Four points are shown on the graph on 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.

What is the cost of one bag of candy? (4 points)

a $2

b $4

c $0

d $6