Starling Co. is considering disposing of a machine with a book value of $23,500 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 68,900. 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 $19,900 if the new machine is purchased. The five-year differential effect on profit from replacing the machine is a(n):.a. decrease of $66,430.
b. decrease of $51,100.
c. increase of $51,100.
d. increase of $66,430.