Tawstir Corporation has 600 obsolete personal computers that are carried in inventory at a total cost of $833,400. If these computers are upgraded at a total cost of $30,600, they can be sold for a total of $657,000. As an alternative, the computers can be sold in their present condition for $596,700.

The sunk cost in this situation is:

$596,700

$30,600

$657,000

$833,400