Which of the following should be documented to ensure that the change management plan is followed?

Documenting the "scope of the change" clearly defines what specifically will be modified, what systems or components are affected, and the boundaries of the change. This is crucial for controlling the execution and ensuring only approved alterations are made, thus ensuring the plan is followed.

While the purpose of the change is important to justify it, it doesn't directly ensure the plan is followed in terms of execution details and boundaries.

The change rollback plan is a critical part of a change management plan, but documenting it alone does not ensure the overall plan (including execution, testing, communication, etc.) is followed; it's a specific contingency element.

Change risk analysis assesses potential impacts, which is part of planning the change, but documenting the analysis itself doesn't directly ensure the steps of the plan are followed during implementation.