(4)Notwithstanding the provision of sub-section (3), one expert having such qualifications as may be prescribed shall be nominated by the Municipal Corporation or the Class 'A' Municipal Council, as the case may be, with the approval of the Government for a period of one year to attend the meetings of the Municipal Accounts Committee.The expert shall be eligible for re-nomination, but the total period, for which he is nominated, shall not exceed three years.