In active full backups, the entire dataset is backed up each time the backup job runs, whereas in synthetic full backups, only the changes since the last full backup are backed up. If the engineer configured the backup job to run active full backups instead of synthetic full backups, it's possible that the data from the full backup taken 60 days ago is still being retained as part of the regular backup process. Therefore, it hasn't been removed automatically after 60 days as expected.

After using Instant VM Recovery to bring a critical crashed server back online quickly, the final step required to complete the recovery process is A: Migrate to production. Instant VM Recovery allows a VM to run directly from the backup file in a temporary location, enabling rapid recovery and minimal downtime. However, because the VM is running in this provisional state, it's essential to migrate it back to the production environment to ensure long-term stability and performance. The "Migrate to production" operation involves moving the running VM from the backup storage to the production storage, typically involving a storage vMotion in VMware environments or a similar process in other hypervisors. This step ensures that the VM is fully restored to its original or a new production environment, solidifying the recovery and allowing the VM to operate as part of the normal infrastructure once again.

To ensure VMs running interdependent applications fail over one by one, as a group, the method to use is D: Failover plan. In Veeam Backup & Replication, a failover plan allows for the orchestration of a group of replicas to fail over in a predefined sequence. This includes the capability to set up delays between starting each VM, which is crucial for interdependent applications that must be started in a specific order to function correctly. The failover plan ensures that dependencies among the group are respected and that the startup sequence follows the correct order, enabling a smooth and organized transition to the failover state.

The Quick Rollback feature can be used during a Full VM Restore to restore only the changed blocks of data since the last backup. This is typically used when the issues are minor and have been caused by VM guest user error, rather than full-scale data corruption or migrations to a different virtualization host. Quick Rollback can efficiently restore the VM to its previous state without the need to transfer the entire VM's data.References:
* Veeam Backup & Replication User Guide: Quick Rollback
* Veeam Help Center: Performing Quick Rollback

To meet the 1-hour RPO for the databases within the VM, while only being able to snapshot the VM once per day, the best strategy is to enable regular transaction log backups (option A) and process transaction logs with the job (option E). This setup allows the system to capture changes in the SQL Server transaction logs at intervals less than the RPO requirement, without needing to snapshot the entire VM more frequently.References:Veeam Backup & Replication Documentation, Veeam Backup & Replication Best Practices Guide