A system administrator would like to modify the system default user characteristics so that each new user will now be assigned （by default） the csh shell rather than the ksh shell. Which of the following actions should be performed？（）

• 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