The correct selection is B. After a sandbox refresh, production-oriented external identifiers can point to invalid records in the UAT integration landscape. A post-refresh process should transform those identifiers to a known UAT-safe mapping so test orchestration remains internally consistent and cannot accidentally target production systems. From an operating perspective, production stability depends on disciplined incident handling, environment synchronization, backup/recovery, observability, and control of configuration drift. Emergency actions can be faster than normal releases, but they still require traceability and must be reconciled back into the managed development baseline. The other options are weaker because they either expose production to unnecessary risk or do not reconcile the operational change back into the governed lifecycle. For this scenario, the decisive point is therefore the platform behavior represented by the selected option (B. In the post refresh plan, modify external ids to a known valid set of values for UAT.). Applying that rule consistently keeps the implementation aligned with Salesforce-supported lifecycle practices and makes the resulting change easier to review, validate, and operate across environments.

Study Guide reference: Operating — production governance; environment drift; incident response; backup/recovery; post-refresh controls; hotfix synchronization.