What is the first program that is usually started, at boot time, by the Linux kernel when using SysV init?

What is the first program that is usually started, at boot time, by the Linux kernel when using
SysV init?

A.
/boot/init

B.
/lib/init.so

C.
/sbin/init

D.
/etc/rc.d/rcinit

E.
/proc/sys/kernel/init