In which of the following cloud models is the customer not responsible for hardware and OS layers but is responsible for the data and the application?

In the Software as a Service (SaaS) model, the cloud provider delivers software applications over the internet, and the customer does not manage any of the underlying infrastructure, including hardware, OS, or even the application itself beyond basic configurations. Customers use the software as a service, which means they are not responsible for the application or data management to the same extent as in PaaS.

Infrastructure as a Service (IaaS) provides customers with virtualized computing resources over the internet. In this model, customers are responsible for managing both the operating system and applications, alongside the data. This option does not fit the requirement since customers have more control over the infrastructure compared to PaaS.

Container as a Service (CaaS) focuses on container management and orchestration. While it provides a level of abstraction similar to PaaS, customers are still responsible for managing the applications and data within the containers. Thus, it does not align with the description where the customer is not responsible for the OS layers.