Which scenario is valid after disconnecting the application from source database B during a migration?

After disconnecting the application from the source database B during a migration, it is important to validate that no additional write operations have occurred on the source database during the migration process. Logging into the source database B allows you to confirm that the intended data has been captured and no further changes are made that could affect consistency and data integrity in the migration.

This validation step is critical because if any write operations occur after disconnection, it could lead to data inconsistencies. Ensuring that there are no unwanted changes verifies that the dataset you are migrating is accurate and complete, allowing for a smooth transition to the target database.

The other scenarios do not align with best practices for managing a safe and effective migration. Deleting the source database before migration would risk losing essential data. Restarting the application immediately could introduce errors or complications, and monitoring from a different account may not provide the necessary access to confirm write operations related to the specific migration process.