Under  which  of  the  following  circumstances  must  a  JFS  filesystem  be  used  instead  of  a  JFS2   filesystem（）

A.Use the reboot command.
B.Edit the /etc/reboot file and reboot the system.
C.Edit /etc/.init.state file and reboot the system.
D.Use the telinit command

A.Use the tcopy /dev/rmtO.l until an end-of-tape error notification is received.
B.Use the cpio -idmv < /dev/rmtO.l until an end-of-tape error notification is received.
C.Use the tar -tvf /dev/rmtO.l repeatedly until an end-of-tape error notification is received.
D.Use the dd if=/dev/rmt0.1 bs=128k count=EOT until an end-of-tape error notification is received.

A.chgrp
B.chuser
C.edit /etc/user
D.edit /etc/security/group