A cook has 6 1/2 cups of sliced carrots, how many 3/4 cup of servings of carrots is this

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.