All the above are correct.
All of these options would help in reproducing, or duplicating, Jenkins jobs and configuration on one or more new servers
A) Directory cloning copies the job directories to generate a copy that can then be used
B) Backup plugins take care of backups so a backup created can be restore on new server with new instances of jenkins data in it
C) Name change allows renaming of folders, something useful when running multiple versions of jobs.
D) Copying directories between installations transfers jobs and configurations between servers.
Because each of these techniques can be applied in different contexts to copy or manage Jenkins data
E) All the above is correct.