Correct Answer: DIn a disaster recovery scenario, it is crucial to ensure that the backup file is encrypted to protect sensitive information like passwords. While TFTP is generally used for transferring files in some scenarios, it does not inherently provide encryption, which makes it unsuitable for secure transfers. On the other hand, SFTP (Secure File Transfer Protocol) ensures that the transfer of backups is encrypted, thus protecting the data in transit. Combined with the requirement for a comprehensive backup, the 'All configuration backup over SFTP' option meets the requirements of both encryption and completeness, making it the best choice for the scenario described.