Review the following program.

What is the possible problem？（）

单项选择题Asystemadministratorhasaserverthatisperformingpoorly.ThevmstatcommandidentifiesthathighCPUusageistheproblem.Whichofthefollowingcommandscanbeusedtoidentifytheeightmostactiveprocessesrunningontheserver？（）

A.ps -ef -t8
B.sar -u -p 8
C.vmstat -t 8
D.topas -p8 -n0 -d0

单项选择题Asystemadministratorisunabletounmountafilesystem.Whichistheappropriatecommandtodeterminewhoorwhatisaccessingthefilesystem？（）

A.who /filesystem
B.lsfs /filesystem
C.fuser /filesystem
D.umount -f /filesystem

单项选择题Asystemadministratorwantstoconfigureasystemsothatallnewuserswillbeputintothedatabasegroupbydefault.Howwouldthisbeaccomplished？（）

A.remove all other groups from the system
B.run the command mkuser -default "GROUP=database"
C.change the default group in /usr/lib/security/mkuser.default
D.edit /etc/security/group to move all users to the database stanza

单项选择题Asystemadministratorwouldliketomodifythesystemdefaultusercharacteristicssothateachnewuserwillnowbeassigned（bydefault）thecshshellratherthanthekshshell.Whichofthefollowingactionsshouldbeperformed？（）

A.Run the command chlogin -shell "csh"
B.Run the command mkuser -default "SHELL=csh"
C.Edit /etc/passwd and change all "ksh" entries to "csh"
D.Modify the contents of /usr/lib/security/mkuser.default file

单项选择题Forsecurityreasons，anadministratorisaskedtomodifythesystemtopreventsomeonefromleavingaterminalloggedin.Toenableafiveminutetimeoutforallusers，whatwouldneedtobedonetoaccomplishthistask？（）

A.Add the following line to /etc/environment：  TMOUT=300
B.Add the following lines to /.profile  TMOUT=5  export TMOUT
C.Execute the following command：  chuser -u ALL -a TIMEOUT=5M
D.Execute the following command：  chsec -u ALL -a TIMEOUT=600