Starling Co. is considering disposing of a machine with a book value of $22,500 and estimated remaining life of five years. The old machine can be sold for $5,200. A new high-speed machine can be purchased at a cost of $70,200. It will have a useful life of five years and no residual value. It is estimated that the annual variable manufacturing costs will be reduced from $23,100 to $20,600 if the new machine is purchased. The differential effect on income for the new machine for the entire five years is a(n)

a.increase of $52,500

b.decrease of $52,500

c.increase of $68,250

d.decrease of $68,250