C. 8$/m. The rate is the same as the slope. To find the slope, we find "rise over run," or the change in the height/change in length (OR, change y/ change x)
The change in y is 24-8=16
The change in x is 3-1=2
16/2= 8$/1 m. This is the unit rate because it describes the change in y over ONE UNIT of x.