Final answer:
The cloud model that represents three healthcare firms jointly owning and sharing the same cloud resources is the community cloud model.
Step-by-step explanation:
The cloud model that represents three healthcare firms jointly owning and sharing the same cloud resources to meet their computing needs is the community cloud model.
A community cloud is a shared computing environment in which resources, such as infrastructure and software, are shared among organizations with common goals or interests.
In this case, the three healthcare firms are pooling their resources and using the same cloud infrastructure to meet their computing needs, which allows them to optimize costs, increase collaboration, and achieve economies of scale.