FutureTek Technologies, Inc. is analyzing a capital project for producing a new type of project management software called FuturePlan. Which of the following is an example of a sunk cost, and should it be included in the cash flows for capital budgeting?

a$.$ Salaries for increased sales staff, include

b$.$ Salaries for increased sales staff, exclude

c$.$ Market research spent researching FuturePlan demand,