Except as provided in subsection (b) of this section, regular interest is payable on member contributions at the rate of 4% a year, compounded annually, until retirement or withdrawal of the accumulated contributions. Except as provided in subsection (c) of this section, no further interest shall be paid on member contributions after membership ends if the former member is not eligible to receive a vested allowance under Title 29, Subtitle 3 of this article. In this subsection, “active member” means a member who is not separated from employment with the State or a participating employer of one of the several systems. This subsection applies only to an individual who: is a former member of the Correctional Officers’ Retirement System; is not eligible to receive a vested allowance from the Correctional Officers’ Retirement System under Title 29, Subtitle 3 of this article; has not withdrawn the individual’s member contributions from the Correctional Officers’ Retirement System; and is an active member of one of the several systems. An individual described in paragraph (2) of this subsection shall receive regular interest at the rate described under subsection (a) of this section on the individual’s member contributions in a nonvested account in the Correctional Officers’ Retirement System while the individual is an active member of one of the several systems.