Ans is C
Crontab For commands that need to be executed repeatedly (e.g., hourly, daily, or weekly), you can use the crontab command. The crontab command creates a crontab file containing commands and instructions for the cron daemon to execute
Init is the parent of all processes. Its primary role is to create processes from a script stored in the file /etc/inittab (see inittab(5)). This file usually has entries which cause init to spawn gettys on each line that users can log in. It also controls autonomous processes required by any particular system.
The gettydefs file supplies the getty command with information about various terminal
attributes, such as the default initialization and the login message. The gettydefs file
contains single line entries that are separated by blank lines. Each entry contains five
fields; each field is separated by a number sign (#). You can indicate comments in the
file by putting a number sign (#) at the beginning of a line.
When the getty command is invoked, it scans the gettydefs file for the first entry with a
matching identifier field (see below). If the gettydefs file cannot be opened, internal
default settings are used. If a match is found, then the matching entry is parsed, and
the terminal attributes are set based on the fields specified in the entry. If a match is
not found, the first gettydefs file entry is used; therefore the first entry in gettydefs
must be the default entry. The maximum length of each entry is 255 characters.
The inittab file describes which processes are started at bootup and during normal operation (e.g. /etc/init.d/boot, /etc/init.d/rc, gettys...). Init(8) distinguishes multiple runlevels, each of which can have its own set of processes that are started.
