Starling Co. is considering disposing of a machine with a book value of $23,400 and estimated remaining life of five years. The old machine can be sold for $5,400. A new high-speed machine can be purchased at a cost of $68,600. 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 $22,800 to $21,000 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 $70,460

b.decrease of $70,460

c.decrease of $54,200

d.increase of $54,200