Which of the following will be required to be able to read the data on an encrypted LTO-4 backup tape, if the tape has to be imported at the DR target site?

LTO tape encryption relies on symmetric encryption keys; without the exact key used during the encryption process, the data on the tape remains unreadable, regardless of the tape drive or other configurations.

An LTO-3 tape drive may not be compatible with LTO-4 tapes for reading, and even if it were, it does not provide the encryption keys necessary to decrypt the data.

A 'plain text cipher key' is a vague term, but generally, the specific encryption key, often managed by a key management system, is required, not a generic plain text string.

IPSec encryption keys and ACLs are used for securing network communications and are not relevant for decrypting data stored offline on a physical backup tape.