According to the PMBOK Guide, the stakeholder engagement plan and the communications management plan are two key project documents that guide the project manager on how to manage stakeholder expectations and communicate project information. The stakeholder engagement plan identifies the stakeholder needs, interests, and level of engagement, and defines the strategies and actions to increase their support and minimize their resistance. The communications management plan specifies the communication requirements, methods, frequency, and formats for each stakeholder or stakeholder group. The project manager should review these plans to determine if the stakeholder requesting the status updates is appropriately engaged and informed, and if any changes are needed to accommodate the request. Reviewing the stakeholder engagement and communications management plans is the best action that the project manager should take in this situation. Starting to send status updates to this stakeholder based on the request (A) may not be appropriate or feasible, as it may violate the communication protocols, overload the stakeholder with unnecessary information, or create inconsistencies with other stakeholders. Asking the stakeholder’s manager if the stakeholder can be added to the list (B) may not be necessary or effective, as it may bypass the stakeholder’s own preference, authority, or influence, or create conflict with the stakeholder’s manager. Escalating the stakeholder’s request to the project sponsor (D) may not be warranted or advisable, as it may indicate a lack of project management skills, create unnecessary involvement of the project sponsor, or damage the relationship with the stakeholder. References: PMBOK Guide, 6th edition, pages 513-514, 537-538.