Westcoast Aeronautics Ltd. spent $7 million eighteen months ago to build a plant for a new product. It then decided not to go forward with the project, so the building is available for sale or for a new product. Which of the following statements is correct? options: a) Since the building has been paid for, it can be used by another project with no additional cost. Therefore, it should not be reflected in the cash flows for any new project. b) If the building could be sold, then the after-tax proceeds that would be generated by any such sale should be charged as a cost to any new project that would use it. c) This building is an example of an externality, because the very existence of the building affects the cash flows for any new project that Westcoast Aeronautics might consider. d) Since the building was built in the past, it is a sunk cost and therefore no additional costs should should be applied if the building were to be used by a new future project.