What is NOT a model of application deployment?

The question requires an understanding of various application deployment models. Among the choices provided, virtualized environments are not classified as a distinct application deployment model like the others.

Containerised applications represent a deployment model that utilizes containers to package software along with its dependencies, ensuring it works uniformly across different environments. Serverless architecture is a modern deployment model where the cloud provider dynamically manages the allocation of machine resources. Cloud-native applications are specifically designed to leverage cloud computing characteristics, such as scalability and resilience.

In contrast, virtualized environments refer to a broader infrastructure concept where multiple virtual instances run on a single physical machine, typically utilizing hypervisors. While virtualization can be part of how applications are deployed—helping to optimize resource usage—it does not represent a standalone deployment model like the others that are aimed at specific architectural approaches to application design and delivery.

Hence, the distinction lies in the focus; the other three choices—containerized applications, serverless, and cloud-native—are more about how applications are designed and built for deployment in specific architectural styles, while virtualization serves as an underlying technology that can support these various models rather than being an application deployment model itself.