问题：

[单选]

An administrator has mirrored the root volume group to a second disk, but 'bootlist' is failing to correctly add the second disk.
What is the likely cause of the problem?（）

A . The administrator has failed to run 'bosboot -ad <2nd disk>' prior to the bootlist command.
B . The administrator has failed to run 'bootinfo -B <2nd disk>' prior to the bootlist command.
C . The administrator has failed to run 'mirrorvg -m rootvg <2nd disk>' prior to the bootlist command.
D . The administrator has failed to run 'bosboot -ad /dev/ipldevice <2nd disk>' prior to the bootlist command.