The graph shows the number of sprays an automatic air freshener dispenses, y, in x minutes: A graph is shown. On the x-axis, the values are from 0 till 150 in increments of 30 for each grid line, and on the y axis, the values are from 0 to 30 in increments of 6 for each grid line. The title of the graph on the x-axis is Time in minutes, and the title on the y-axis is Number of Sprays. A line is shown connecting points on ordered pair 30, 6 and 60, 12 and 90, 18 and 120, 24. The title for the graph is Dispense Rate.

Which expression can be used to calculate the rate per minute at which the air freshener dispenses sprays?

A. 30/6
B. 24/30
C. 30/24
D. 6/30