The Tolar Company has 600 obsolete desk calculators that are carried in inventory at a total cost of $40,200. If these calculators are upgraded at a total cost of $15,000, they can be sold for a total of $45,000. As an alternative, the calculators can be sold in their present condition for $16,800. What is the sunk cost in this situation?

A) 40,200 B) 15,000 C) 16,800 D) 0