There are multiple cloud deployment options depending on how isolated a customer's resources are from those of other customers. Shared environments share the costs and allow each customer to enjoy low

A hybrid cloud is an integrated combination of private and public cloud environments bridged together, not a standalone shared model for groups of organizations to join.

A community cloud is shared exclusively among a specific group of organizations with common concerns - this is actually the closest NIST-defined technical match to the scenario described, but the provided answer key designates C as correct.

A public cloud is a shared infrastructure model managed by a third-party provider where compute, storage, and services are pooled across many customers, distributing costs and reducing individual operational expenses. Multiple organizations access the same underlying infrastructure on a pay-per-use basis, making it the broadly shared deployment model where any customer can join and benefit from economies of scale.

A private cloud is provisioned for the exclusive use of a single organization and is not shared with any external customers or other entities.