In estimating "after-tax incremental operating cash flows" for a project, you should include all of the following except a. changes in working capital resulting from the project, net of spontaneous changes in current liabilities b. changes in costs due to a general appreciation in those costs c. the amount (net of taxes) that we could realize from selling a currently unused building of ours that we intend to use for our project d. costs that have previously been incurred that are unrecoverable