Every night a datacenter takes snapshots of each VM and backs them up to a tape which is shipped off to a disaster recovery site once a week. Which of the following can mitigate a security breach if…

Transmission level encryption protects data as it moves across a network, but it does not protect data stored on a physical medium like a tape once it is offline and in transit.

Transport layer encryption (like SSL/TLS) protects data in transit over a network, but it does not secure data that has been written to a physical medium and is being physically transported.

Hard drive encryption, or more broadly, media encryption for tapes, encrypts the entire physical storage medium at rest. If the tapes are lost or stolen during physical transport, the data stored on them would be inaccessible and unreadable without the correct decryption key, thereby preventing a security breach.

File level encryption encrypts individual files, but it might not cover all metadata or system areas on the tape, and is generally applied to active filesystems rather than an entire backup medium.