Question: What is a cave diving organisation which was formed in September 1973 that administers and supports cave diving activity in other parts of Australia including the Nullarbor Plain and  a town in inland New South Wales, Australia, located at the junction of the Macquarie and Bell Rivers?
Sentence (from "Murrawijinie Cave"): Marrawijinie Cave is cave located in the Australian state of South Australia within the gazetted locality of Nullarbor on the Nullarbor Plain.
Relevant evidence: No