In AWS, what does the term ‘availability zone’ refer to?

The term ‘availability zone’ in AWS refers to an isolated location within a region. Each region in AWS is comprised of multiple availability zones, which are essentially distinct data centers that are isolated from failures in other availability zones. This design enhances the resilience and reliability of applications because if one availability zone experiences issues, the applications running in other availability zones can continue to operate without interruption.

By distributing resources across multiple availability zones, users can achieve fault tolerance and high availability for their applications. This geographical separation also allows for improved disaster recovery strategies, as data can be replicated across zones.

The other choices describe different concepts that do not align with the specific technical operation and design of AWS infrastructure. A global network of servers reflects the broader distribution of AWS's services but does not capture the localized nature of availability zones. Backup storage options relate to services like Amazon S3 or AWS Backup, while a virtual private network connection pertains to secure networking but is unrelated to the concept of availability zones. Thus, option B accurately defines what an availability zone is within the context of AWS.