I would say the correct answer would be Southeast Asia. The first Australians migrated from Southeast Asia. It was believed that the very first Australians were from an Asian population so from the choices it should be the correct answer.
Answer: I would have to say either A or C, im a little more confident in C tho :)
Explanation: Brainliest is awlays helpful
Xerxes behaved Eager and decisive
Assimilation, you were right !