Which of the following keys are used to access advanced Windows start up options while a computer is booting？（）

A.REGEDIT
B.SYSEDIT
C.MSCONFIG
D.CHKDSK

A.the BIOS settings are incorrect.
B.there is no floppy disk in the drive.
C.the computer was unable to make temporary space for the boot process.
D.the computer was unable to find the information needed to start the boot process.