What is an Availability Zone?
A location where users can deploy compute storage, database and other select AWS services where no AWS Region currently exists
One or more discrete data centers with redundant power, networking and connectivity
One or more clusters of servers where new workloads can be deployed
A fast content delivery network (CDN) service that securely delivers data videos applications and APIs to users globally
Explanations:
An Availability Zone is not a location where no AWS Region currently exists; rather, it is a part of an existing AWS Region, providing high availability and fault tolerance within that Region.
An Availability Zone consists of one or more discrete data centers, each with independent power, cooling, and physical security, ensuring high availability and redundancy.
While an Availability Zone does host clusters of servers, the definition is more specific as it focuses on the physical infrastructure and redundancy rather than simply being a location for deploying workloads.
This option describes a content delivery network (CDN) service, which is not related to Availability Zones; they are used for different purposes in AWS architecture.
I map out that the answer is:
One or more discrete data centers with redundant power, networking and connectivity