The graph shows the number of paintballs a machine launches, y, in x seconds:
Which expression can be used to calculate the rate per second at which the machine launches the balls? (5 points)
A. 80/40
B. 20/4
C. 4/80
D. 4/20
![The graph shows the number of paintballs a machine launches y in x seconds Which expression can be used to calculate the rate per second at which the machine l class=](https://us-static.z-dn.net/files/d07/c4d052e24ea087c3867b1772300c6c0d.jpg)