Which combination of actions must a solutions architect take to meet these requirements?

Explanations:

Creating an ongoing replication task is essential for keeping the Aurora PostgreSQL database synchronized with the on-premises PostgreSQL database during the migration. This allows real-time data changes to be replicated to Aurora, ensuring both databases remain consistent while the migration is in progress.

Creating a database backup of the on-premises database is not necessary for maintaining synchronization between the two databases during the migration. While backups are important for disaster recovery and initial data transfer, they do not facilitate ongoing synchronization.

Creating an AWS DMS replication server is required to facilitate the ongoing replication of data from the on-premises PostgreSQL database to the Amazon Aurora PostgreSQL instance. The replication server handles the continuous data flow needed to keep both databases in sync throughout the migration process.

Converting the database schema using the AWS Schema Conversion Tool (AWS SCT) is part of the migration process but does not directly relate to maintaining synchronization between the on-premises and Aurora databases. Schema conversion is a preparatory step for the migration rather than an ongoing synchronization mechanism.

Creating an Amazon EventBridge rule to monitor database synchronization does not directly ensure synchronization between the databases. While monitoring is important, it does not actively manage or facilitate the ongoing replication process that keeps the two databases in sync during migration.