Final answer:
The correct answer is D. Region. AWS clusters data centers in physical locations called regions.
Step-by-step explanation:
The correct answer is D. Region. In AWS (Amazon Web Services), a region is a physical location around the world where AWS clusters their data centers. Each region is completely independent and is designed to be isolated from other regions to ensure fault tolerance and high availability. AWS currently has multiple regions worldwide, including regions in North America, South America, Europe, Asia Pacific, and the Middle East.