Alfred has a lawn service. He earns $40 for every 3 lawns he mows. Which of the following represents the rate of change of his income with respect to the number of lawns he mows? Responses $504 lawns $ 50 4 lawns 4 lawns$50 4 lawns $50 $53.334 lawns $53.33 4 lawns 4 lawns$53.33