Infrastructure as a Service model is correct.

Infrastructure as a Service model follows a shared responsibility model at the infrastructure layer because the cloud provider is responsible for the physical datacenter, physical hosts, networking, and the virtualization layer while the customer is responsible for the guest operating system, applications, data, and access controls. These overlapping duties mean both parties share responsibility for protecting data privacy related to the infrastructure.

Software as a Service is incorrect because the provider manages the application stack and most of the infrastructure and data handling responsibilities, which leaves the customer with far less responsibility at the infrastructure layer.

Platform as a Service is incorrect because the vendor controls the platform runtime and much of the underlying infrastructure, and the customer focuses on code and data, so the division of responsibility at the infrastructure layer is different from IaaS.

Desktop as a Service is incorrect because it is a managed desktop offering in which the provider typically manages the underlying infrastructure and desktop images, and it does not represent the standard IaaS shared responsibility split at the infrastructure layer.

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