单项选择题 In order to change the system runlevel and execute /etc/inittab entries based on the new runlevel, which of the following commands should be performed?（）

单项选择题 A user reports a corrupted boot logical volume. In order to recreate the contents of the boot logical volume which of the following procedures should the user be advised to perform?（）

单项选择题 A graphics card has been added to the system. After rebooting, the system hangs during the login process with a blue screen indicating "CDE please wait". Which of the following procedures should be performed next?（）