Oliver Industries is evaluating the manufacturing process for one of their products. Oliver has determined that the process has yearly maintenance costs of exist29,000, yearly operating costs of exist22,000, and yearly revenues of exist97,000. Two years ago, the firm spent exist6,000 upgrading the equipment used to make this product, and it expects to spend exist5,000 on additional upgrades three years from now. In this scenario, Oliver:.
a) has sunk costs of exist5,000.
b) has sunk costs of exist6,000.
c) has sunk costs of exist51,000.
d) does not have any sunk costs.