Which of these is not one of the six states of Australia?

Option C

The Australian Capital Territory (ACT), known as the Federal Capital Territory (FCT) until 1938, is a federal territory of Australia containing the Australian capital city of Canberra and some surrounding townships. It is located in the south-east of the country and is an enclave within the state of New South Wales.

There are six states: New South Wales, Victoria, Queensland, Western Australia, South Australia and Tasmania. Historically, each is a successor to one of the previous Australian colonies. Each state has its own constitution, with its own legislature (parliament), judiciary and executive. The state parliaments have plenary legislative power, except that some areas of legislative power are exclusive to the Federal Parliament, many others are exercised concurrently with it and, in case of conflict between federal and state legislation, the federal legislation prevails. A decision of a state judiciary is subject to appeal to the High Court.