Sec. 5. The assets assigned to a closed block shall be specified in the plan of operation and must consist of:
(1) a list of designated assets of the converting mutual's general account or specified segments of the converting mutual's general account, which list shall change periodically to reflect the acquisition and disposition of assets;
(2) a designated portion of each and every asset of the converting mutual's general account or specified segments of the converting mutual's general account, which portion shall change periodically to reflect the cash flows of the closed block; or
(3) assets designated by a combination of the methods described in this section.