an equipment bought four years ago for ​$4 comma 760 has a current market value of ​$2 comma 380 . if kept for one more​ year, it will cost ​$1 comma 700 in operation and maintenance costs and will have a market value of ​$1 comma 950 at the end of the year. in conducting a replacement analysis for the​ equipment, which of those cash flows can be considered a sunk​ cost?