Any bank, capital stock financial institution, or qualifying mutual financial institution located in the county may apply for the privilege of keeping money upon the following conditions: All deposits shall be subject to payment when demanded by the county treasurer on his or her check or order and subject also to such regulations as are imposed by law and the rules adopted by the county treasurer for holding and receiving such deposits. It shall be the duty of the county board to act on the application or applications of any and all banks, capital stock financial institutions, or qualifying mutual financial institutions, state or national, as may ask for the privilege of becoming the depository of such money, as well as to approve the bonds of those selected incident to such relation, and the county treasurer shall not deposit such money or any part thereof in any bank, capital stock financial institution, or qualifying mutual financial institution other than such as may have been so selected by the county board for such purposes, if any such bank, capital stock financial institution, or qualifying mutual financial institution has been so selected by the county board.