For security reasons， an administrator is asked to modify the system to prevent someone from leaving a terminal logged in. To enable a five minute timeout for all users， what would need to be done to accomplish this task？（）

• 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