List the stakeholders in approving the ProjectManagement Plan

List the stakeholders in approving the ProjectManagement Plan?

The answer is project manager with functional manager and project sponser.

 Can anyone explain how come a project Manager whose working on the PM plan approve his/her artifact.

 Because some significant work might be peformed from the Project Management Team, not only by Project Manager.

 I think the answer is not correct.  PM Plan will be developed by the project team (PM, team members) and also gets inputs from all subsidiary plans. Hence it has to be approved by the key stakeholders.