The regular term of office of each county commissioner, when the commissioner is elected for a full term, commences on the first Monday in December next succeeding the officer’s election and each such commissioner shall qualify and enter upon the discharge of the commissioner’s duties on or before the first Monday in December next succeeding the date of the commissioner’s election or within ten days thereafter. If a commissioner is elected to fill an     unexpired commission term held by an appointee, such officer may qualify and enter upon the discharge of the duties of such office at any time after receiving a certificate of election to that office but not later than the first Monday in December next succeeding the date of the commissioner’s election to the unexpired term of office.