In accordance with this section, a school board may adopt regulations relating to lobbying of members of the school board and of officials and employees of the school system. The lobbying regulations adopted by a school board under subsection (a) of this section: shall be substantially similar to the provisions of Subtitle 7 of this title; but may be modified to the extent necessary to make the provisions relevant to that school system; and may be further modified to the extent considered necessary and appropriate by and for that school system. Unless a school board adopts and maintains lobbying regulations under this subtitle, the provisions enacted by the county under § 5–810 of this subtitle shall apply to that school system.