Which of the following actions will accomplish this?

Files created in the /home/ourgroup directory need to automatically have group ownership that is identical to the directory itself. Which of the following actions will accomplish this?

A.
Assign private permissions on the directory using hown g+s /home/ourgroup

B.
Set the sticky bit using hmod 2770 /home/ourgroup

C.
Set permanent permissions on the directory by running kdir g+s /home/ourgroup

D.
Set the SGID bit using hmod g+s /home/ourgroup