What must be done to allow only users of the devel system group to access a share?

A.
In the smb.conf file, set valid users = @devel

B.
In the smb.conf file, set valid groups = @devel

C.
In the smb.conf file, set valid groups = devel

D.
chgrp the directory on the Samba server to the devel group, and then set the GID bit on the directory.