A system is being booted into maintenance mode due to root password recovery.After accessing the root volume group and starting a shell without mounting the file systems, what is the next step?（）

A. Delete root's password from the /etc/security/passwd file
B. Use the diag recovery tool option to reset root's password
C. Execute the ‘passwd’ command and assign a new passwd to root UID
D. Mount the / and /usr filesystems on alternative mount points to edit the password file