Which TWO runlevels should never be declared as the default runlevel?
A.
0
B.
3
C.
5
D.
6
Explanation:
From the man pages:
Runlevels 0, 1 and 6 are reserved. Runlevel 0 is used to halt the system and 6 to reboot the system. Runlevel 1 is used to bring the system back down into single-user mode.
Answer A. 0 means Shutdown and D. 6 means Restart. These two numbers we can not put as default runlevel.
0
0