Answer: d. difference between future cost savings and the new equipment's costs.
Step-by-step explanation:
When deciding whether or not to replace old equipment, the main thing the company should be concerned about is if the new equipment is worth it. This worth will be measured by how much it saves for the company over the old equipment vs its cost.
If the cost of the equipment is less than the future savings it will bring in, it should be bought to replace the old equipment because it would be contributing more than it costs. If the reverse is true then it should not be bought.