ID Tech is considering whether to purchase a new mail sorting machine costing $459,000 or pay $415,000 to refurbish its current machine that was originally purchased 5 years ago at a cost of $423,000. Management is also considering dropping its mail product offering altogether and instead of either investment, use the funds to invest in another project that is projected to return a total of $483,000.

1. In making a decision to purchase a new machine rather than refurbish the current machine, the sunk cost was:

2. In making the decision to purchase a new machine rather than refurbish the current machine, the differential cost was:

3. If ID Tech decided to refurbish its current machine and continue its mail product offering, which of the following represented its opportunity cost?