CMG Construction Purchased a Truck 6 Years Ago at a Cost

CMG Construction purchased a truck 6 years ago at a cost of $68,000. Because the old truck required an overhaul of $4,000 last year, and repairs of $2,000 are needed in the current year, the company is now planning to purchase a new truck to replace the old one. The old truck has a trade-in value of $5,000. The cost of the new truck is $82,000. What amount of these costs represent sunk costs?

A) $68,000
B) $72,000
C) $77,000
D) $79,000