(a) If a retiree who is receiving a disability retirement annuity returns to state service or if the retiree is found to be no longer incapacitated for the further performance of duty, the person must again become a member of the retirement system or, if the person holds a position included in the elected class of membership, may elect to become a member. If a person becomes a member under this section, the executive director shall terminate the person's annuity payments.
(b) A person who becomes a member under this section is entitled to service credit for all service previously established and not canceled by a withdrawal of contributions.
(c) If a person's disability retirement annuity is discontinued under this section, the person's selection of any optional annuity becomes void.