What is the MOST cost-effective solution?

Explanations:

Migrating to Amazon Redshift may improve reporting performance due to its optimized analytical capabilities, but it would involve additional costs for data migration, storage, and maintenance, making it less cost-effective compared to simply optimizing the existing setup.

Using an Aurora Replica can offload read traffic from the primary instance, thereby reducing CPU and IOPS load on the main database during heavy reporting periods. This solution is typically more cost-effective than upgrading instance sizes or IOPS because it utilizes existing infrastructure and only incurs costs for additional replicas.

While migrating to a larger instance class may temporarily alleviate performance issues, it can significantly increase costs without addressing the root cause of high read operations during reporting. Additionally, it doesn’t optimize the workload separation.

Increasing Provisioned IOPS may improve performance, but it directly incurs additional costs and does not effectively address the underlying issue of high read operations during reporting. This option is less efficient than creating an Aurora Replica for offloading workloads.