A user with the userid of ’joe’ is unable to rsh from SYSTEMA to SYSTEMB without having to retype their password， but they can rsh from SYSTEMB to SYSTEMA.  No other users are experiencing the same issue.Both systems have a /home/joe/.rhosts file that contain the proper references to the other host. The /home/joe/.rhosts files on both SYSTEMA and SYSTEMB are owned by userid ’joe’.  Which of the following is the most likely cause of this problem？（）

A.employ NIS to synchronize user names and passwords
B.create a /.rhosts on server A and serve B
C.create a $HOME/.netrc for all users on server A and serve rB
D.create a /etc/hosts.equiv on server A and server B

A.The user "jsmith" can use r-commands from any server to server Alpha system-wide
B.The user "jsmith" can use r-commands from server Alpha to any server system-wide
C.The user "jsmith" can use r-commands from server Alpha to any server with a /home/jsmith directory
D.The user "jsmith" can use r-commands from any server to server Alpha only in the /home/jsmith directory

A.Use ’prtconf -c’ to see if the system is 64-bit enabled
B.Check the /etc/inittab to see if /etc/method/cfg64 is enabled
C.Use the ls -al to see if /unix is linked to /usr/lib/boot/unix_64
D.Use the lslpp command to see if the bos.mp64 fileset is installed