What are you doing when you make a decision at the margin?

refusing to make a choice

reviewing several options of how to use one additional unit of a resource

taking an all or nothing approach to a problem

examining two primary options and their trade-offs before making a decision

A4-year project has an annual operating cash flow of $59,000. at the beginning of the project, $5,000 in net working capital was required, which will be recovered at the end of the project. the firm also spent $23,900 on equipment to start the project. this equipment will have a book value of $5,260 at the end of the project, but can be sold for $6,120. the tax rate is 35 percent. what is the year 4 cash flow?