Nighthawk Inc. is considering disposing of an old machine with a book value of $22,500 and an estimated remaining bife of three years. The old machine can be sold for $6,250. A new machine with a purchase price of $68,750 is being considered a replacement. It will have a useful Me of three years and no residual value. It is estimated that the annual vanable manufacturing costs will be reduced from $43,750 to $20,000 if the new machine is purchased. The three-year differential effect on profit from replacing the machine is a(n) Ox. $11.250 dec Ob. $0.750 Oc. $0,750 decrease Od. 12,825 deca