The State shall be divided by law into legislative districts for the election of members of the Senate and the House of Delegates. Each legislative district shall contain one (1) Senator and three (3) Delegates. Nothing herein shall prohibit the subdivision of any one or more of the legislative districts for the purpose of electing members of the House of Delegates into three (3) single-member delegate districts or one (1) single-member delegate district and one (1) multi-member delegate district.