In this Part--
"accountable authority" for a former reporting GSF agency means--
(a) for an entity that has not also ceased to be a GSF agency--the accountable authority for the GSF agency, or
(b) for an entity that has also ceased to be a GSF agency--(i) if the entity has not become part of another GSF agency--the accountable authority for the GSF agency immediately before it ceased to be a GSF agency, or(ii) if the entity has become part of another GSF agency--the accountable authority for that other GSF agency, or(iii) any other entity given a written direction by the Treasurer to exercise the functions of the accountable authority for the entity.