(a) The qualified voters of each county shall elect an assessor-collector of taxes for the county, except as otherwise provided by this section.
(b) In any county having a population of less than 10,000 inhabitants, as determined by the most recent decennial census of the United States, the sheriff of the county, in addition to that officer’s other duties, shall be the assessor-collector of taxes, except that the commissioners court of such a county may submit to the qualified voters of the county at an election the question of electing an assessor-collector of taxes as a county officer separate from the office of sheriff. If a majority of the voters voting in such an election approve of electing an assessor-collector of taxes for the county, then such official shall be elected at the next general election for the constitutional term of office as is provided for other tax assessor-collectors in this state.

(c) An assessor-collector of taxes shall hold office for four years; and shall perform all the duties with respect to assessing property for the purpose of taxation and of collecting taxes, as may be prescribed by the Legislature.