Tawstir Corporation has 800 obsolete personal computers that are carried in inventory at a total cost of $1,100,000. If these computers are upgraded at a total cost of $40,000, they can be sold for a total of $750,000. As an alternative, the computers can be sold in their present condition for $690,000. The sunk cost in this situation is:

$40,000

$750,000

$690,000

$1,100,000