Final answer:
An availability zone is typically a set of one or more data centers with redundancy, within a single region, designed to offer high availability and maintain operations independently from other zones.
Step-by-step explanation:
An availability zone is a concept used in cloud computing, where it typically represents one or more discrete data centers with redundant power, networking, and connectivity that are located within a region.
It is designed to be an isolated zone that remains operational even if another zone within the region fails. Therefore, the setup that can be deployed as an availability zone is B. Two datacenters located in the same region. This allows for the isolation needed for high availability, while still being close enough to provide low-latency network connections.