The Tingey Company Has 500 Obsolete Microcomputers That Are Carried

The Tingey Company has 500 obsolete microcomputers that are carried in inventory at a total cost of $720,000. If these microcomputers are upgraded at a total cost of $100,000, they can be sold for a total of $160,000. As an alternative, the microcomputers can be sold in their present condition for $50,000.
-The sunk cost in this situation is:

A) $720,000
B) $160,000
C) $50,000
D) $100,000