In which cloud service model is the customer required to maintain and update only the applications?

The correct answer is that in the Platform as a Service (PaaS) model, the customer is primarily responsible for maintaining and updating only the applications they develop and deploy on the platform.

In a PaaS environment, the cloud provider manages the underlying infrastructure, including the servers, storage, networks, and runtime environment. This allows developers to focus on writing and managing their applications without worrying about the complexities of the infrastructure. They are typically provided tools and services necessary for application development, deployment, and management, which further simplifies their responsibilities.

The responsibility for maintaining the applications lies primarily with the customer, who must ensure that the applications are updated and functioning as intended. This level of abstraction is beneficial for developers looking to create applications quickly without needing to manage the underlying infrastructure or platform security. As such, PaaS strikes a balance between control over application development and minimizing the operational overhead associated with managing infrastructure.