Starling Co. is considering disposing of a machine with a book value of $25,000 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 $23,000 to $20,600 if the new machine is purchased. The differential effect on Income for the new machine for the entire five years is Oa decrease of $64,480 Ob increase of $64,480 Oc increase of 549,600 Od decrease of 349,600