(a) Delegates to the county convention shall be elected in accordance with respective political party rules.
(b) The county committee may place on the ballot of the primary election the names of all persons seeking election as a county convention delegate who shall have filed a written pledge to abide by the results of the primary, if any is required by the rules of the political party, and shall have paid the ballot fee, if any, assessed therefor.
(c) If candidates for county convention delegates have not qualified as herein provided within the time required for candidates to qualify, the county committee shall select candidates or delegates to the county convention at any public meeting of the committee held after the ticket has closed and prior to the time the primary election ballots are printed.
(d) Any vacancies existing or occurring in any of the positions of delegates after the primary election or elections have been held may be filled by the county committee.