Use the image to answer the question.
An illustration shows Quadrant 1 of a coordinate plane. The x-axis is labeled Ounces and ranges from 0 to 15 in 3 unit increments. The y-axis ranges from 0 to 153 in 9 unit increments. The graph is titled Calories per Ounce. A line connects five points plotted on the graph. The coordinates of the plotted points are (0 , 0), (3 , 36), (6 , 72), (9 , 108), and (12 , 144).
The proportional relationship between calories and ounces of soda is shown in the graph. How many calories are in 1 ounce? (1 point)