What happens to user email addresses during a sandbox refresh?

During a sandbox refresh, user email addresses are modified to avoid production email overlap. This is a crucial aspect of maintaining data integrity and avoiding confusion between sandbox and production environments. If the email addresses in the sandbox were to remain unchanged, it could lead to scenarios where test data or communications might inadvertently be sent to actual production users, which would compromise the privacy and operational workflow of the organization.

By modifying the email addresses, it ensures that all testing and development activities within the sandbox do not affect production users, maintaining a clear separation. This allows developers and testers to work on their projects without risking interference or disruptions to real-world operations. The other options would either lead to significant operational risks or not accurately reflect the procedures followed during a sandbox refresh.