The correct answer is A, 'Availability Zone'. An Availability Zone (AZ) in AWS is one or more discrete data centers within the same geographic region that are connected through low-latency, high-throughput, and highly reliable infrastructure. AZs are designed to operate independently; if one AZ fails, the others continue to function, providing a resilient environment for applications. This setup ensures high availability and fault tolerance for mission-critical applications. The other options, such as Edge location (B), AWS Region (C), and Private networking (D), do not accurately describe the concept of isolated data centers within a region interconnected by low-latency networks.