Which command needs to be run only once to ensure this setting?

The size of the System Global Area (SGA) is 2 GB. You want to ensure that the shmmax parameter is set correctly for each startup of the machine. Which command needs to be run only once to ensure this setting?

A.
cd /proc/sys/vm
echo 2147483648 > shmmax

B.
cd /proc/sys/kernel
echo 1073741824 > shmmax

C.
cd /proc/sys/kernel
echo 2147483648 > shmmax

D.
vi ./skel/.bashrc
…
kernel.shmmax = 2147483648
…

E.
vi /etc/sysctl.conf
…
kernel.shmmax = 2147483648
…