What should the project manager do first?

In the beginning of project execution, the project manager finds out that a key resource will be unavailable for two weeks which could cause a delay to the schedule.

What should the project manager do first?
A . Assign the tasks to another resource, and ask the resource to work double shifts
B. Update the schedule to reflect the project’s changes in duration
C. Ask human resources (HR) for a replacement, and update the nsk register
D. Update the resource management plan and resource allocation chart accordingly

Answer: D