A project sponsor informs the project manager that the project completion date must be moved one month earlier. Which of the following should the project manager do NEXT?

A. Recalculate the critical path, determine the new cost, schedule baselines, and initiate the change request process.
B. Recalculate the schedule and cost variance, and report the changes to the project stakeholders and sponsor.
C. Calculate the cost of crashing the schedule, and obtain the stakeholders' approval for the new project WBS and timeline.
D. Calculate the additional resource requirements that are necessary to meet the new project deadline, and work with human resources to hire additional staff.