Starling Co. is considering disposing of a machine with a book value of $24,400 and estimated remaining life of five years. The old machine can be sold for $5,300. A new high-speed machine can be purchased at a cost of 66,900. 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 $20,500 if the new machine is purchased. The differential effect on income for the new machine for the entire five years is a. decrease of $48,600 Ob. decrease of $63,180 c. increase of $48,600 Od. increase of $63,180