About 470,693 square miles (1.22 million km²)
I have a chance that the answer is A.
Answer:
China's civilization did not die out but continues today
or
China's civilization is the oldest continuous civilization in the world.
Explanation:
A. In the early 1900s
According to australia.gov.au :
"Australia became an independent nation on 1 January 1901 when the British Parliament passed legislation allowing the six Australian colonies to govern in their own right as part of the Commonwealth of Australia".