You need to change the default run-level for the machine. Which file do you need to edit? (Write the full path including the filename)

A.
/etc/init.d

B.
/etc/init-table

C.
/etc/inittab

D.
/etc/init

Explanation:
The file /etc/inittab contains the default run level as well as run level specific scripts.
id:3:initdefault:
If you haven’t specified the run level system boots on run level 9 that is unknown run level.