The Scale-Out Backup Repository feature was introduced in the Enterprise Plus edition of Veeam Backup & Replication. Specifically, this feature allows for creating a single scalable repository by aggregating multiple backup storage locations (referred to as extents). The Enterprise Plus edition provides the flexibility to have an unlimited number of repositories and extents, making it suitable for large-scale environments where extensive storage management is needed. Therefore, for anyone looking to make use of the Scale-Out Backup Repository feature, the correct option would be the Enterprise Plus edition.