Which practice reduces the size of backups and improves backup and restore times?

Data deduplication is the correct choice as it specifically targets the reduction of backup sizes and improves both backup and restore times by eliminating redundant copies of data. This technique works by identifying and removing duplicate data blocks or files, so only unique instances are stored. As a result, storage requirements are minimized, leading to quicker backup processes since there is less data to transfer. During restoration, the time is also reduced since only the unique data needs to be re-established, rather than multiple identical pieces.

The other options, while related to data management and backup efficiency, serve different purposes. Data compression reduces file sizes but does not prevent duplicate data from being stored. Incremental backup focuses on saving only the data that has changed since the last backup, which can improve speed but does not fundamentally decrease the overall amount of data stored. Data archiving deals with moving infrequently accessed data to a separate storage location, which is useful for long-term data retention but does not directly address backup size or speed.