A critical server acquisition for a critical-path activity hasn't arrived, causing schedule and cost impacts. The responsible team member says they sent multiple emails to the supplier but got no reply. Which document would help prevent this situation?

The Communications Management Plan defines how, when, and by whom project information will be communicated. A well-defined plan would have specified the communication methods, frequency, and responsibilities for critical supplier interactions, including follow-up protocols or alternative contact methods, thus preventing a simple lack of reply from escalating. The Escalation Process is a procedure for handling issues that have already become problems, which this situation has. The Statement of Work (SOW) details the deliverables and scope of work for a vendor but doesn't specify communication protocols. The Stakeholder Register identifies stakeholders and their communication requirements but doesn't detail the specific communication plan for project execution.