Oceania's Indigenous settlement began 60,000 years ago, but due to its vastness and diverse arrival times, completion can't be pinpointed to a single year. Please specify region or definition for a more accurate answer.
Unfortunately, none of the provided options (1200 BCE, 120 BCE, 120 CE, or 1200 CE) are the correct answer to the question of "By what year was Oceania's Indigenous settlement complete?"
Here's why:
Oceania is a vast region: Consisting of thousands of islands spanning a massive area, it's impossible to pinpoint a single year for the completion of Indigenous settlement across the entire region.
Varied settlement timelines: The timeline of Indigenous arrival and settlement varies significantly across different areas of Oceania. Some islands were settled as early as 60,000 years ago, while others were inhabited much later.
Ongoing Indigenous presence: Indigenous communities in Oceania have continuously inhabited and adapted to their environments for millennia. There was no single point in time when settlement "completed."