Which data-protection policy moves data that is no longer used to a separate storage device for long-term maintenance?

The correct choice is data-archiving because this policy specifically involves moving data that is no longer actively used to a separate storage device for long-term maintenance. Archiving is a strategic approach to manage data longevity while freeing up primary storage resources for current, actively used data. It ensures that important data is preserved even if it is not accessed frequently, making it available for future needs such as regulatory compliance or historical reference.

This is distinct from other policies such as data-retention, which focuses more broadly on how long data should be kept and under what circumstances it should be disposed of, rather than specifically moving it to a separate long-term storage. Data classification involves categorizing data based on its sensitivity and importance but does not inherently involve relocating it. Data-deletion entails permanently removing data from storage, which is contrary to the concept of archiving, where the goal is to keep data accessible for the long term.