The right answer is Australia, Papua New Guinea and New Zealand
Explanation: Papua New Guinea became an independent Commonwealth realm in 1975 with Elizabeth II as its queen. It also became a member of the Commonwealth of Nations in its own right.
On 1 January 1901, federation of the colonies was achieved after a decade of planning, consultation and voting. This established the Commonwealth of Australia as a dominion of the British Empire.
New Zealand is a constitutional monarchy with a parliamentary democracy, although its constitution is not codified. Elizabeth II is the Queen of New Zealand and thus the head of state.