A project manager is near the end of a large and complex project which required the services of several different vendors. Currently the project manager is about to start the process of finalizing all activities for project closure. Of the following what should the project manager do first? a. Revise and finalize the business case and the project charter b. Update all applicable project documents and mark them as final versions c. Begin the alternative dispute resolution procedure with the vendors d. Submit a change request to update the project management plan