Baxter Bakers is trying to decide whether it should keep its existing bread$-$making machine or purchase a new one that has technological advantages $($which translate into cost savings$)$ over the existing machine. Information on each machine follows:

Old machine New machine

Original cost $$10,000$ $$25,000$

Accumulated depreciation $6,0000$

Annual cash operating costs $9,5005,000$

Current salvage value of old machine $2,500$

Salvage value in $10$ years $6501,200$

Remaining life $12$ yrs $12$ yrs

Refer to Baxter Bakers. The estimated $$650$ salvage value of the existing machine in $10$ years represents a$($n$)$

Select one:

a$.$ sunk cost

b$.$ opportunity cost of keeping the existing machine for $10$ years

c$.$ opportunity cost of selling the existing machine now

d$.$ opportunity cost of keeping the existing machine and buying the new machine