An administrator needs to change a system’s run level from level 2 to level 3. What is the appropriate  method to accomplish this（）

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