What does the intrinsic function Fn::GetAZs return?

Fn::GetAZs is an intrinsic function used in AWS CloudFormation templates to return a list of Availability Zones within a specified region. When invoked without specifying a region, it defaults to the region where the template is being executed. This function is particularly useful for creating resources that are designed to be highly available and fault-tolerant, as it allows users to easily define configurations that can distribute resources across multiple Availability Zones.

The returned array can then be leveraged to create resources, such as EC2 instances or other services, across different Availability Zones, thereby enhancing the application's resilience against zone-specific outages. This function supports the principle of best practices in cloud architecture, which emphasizes the distribution of resources to avoid single points of failure.

By correctly identifying the array of Availability Zones that the function retrieves, it demonstrates an understanding of how AWS CloudFormation can be utilized to automate the infrastructure setup in a way that aligns with AWS architecture best practices.