Valley Forge and Metal purchased a truck five years ago for local deliveries. Which one of the following costs related to this truck is the best example of a sunk cost? Assume the truck has a usable life of eight years.
New tires that will be purchased this winter
Costs of repairs needed so the truck can pass inspection next month
Money spent last month repairing a damaged front fender
Engine tune-up that is scheduled for this afternoon
Cost for a truck driver for the remainder of the truck's useful life