Correct. In IaaS (e.g., Azure Virtual Machines), you select and can install an operating system and are responsible for OS configuration, updates, and security hardening. This aligns with the shared responsibility model: Microsoft manages the physical datacenter and virtualization layer, while you manage the guest OS and above. Installing an OS is a hallmark capability of IaaS.
Incorrect. In PaaS (e.g., Azure App Service, Azure SQL Database), the cloud provider manages the operating system and platform components. You manage your application code and configuration, but you typically cannot install or administer the underlying OS. You may choose runtimes or frameworks, but that is not the same as installing an OS.
Incorrect. In SaaS (e.g., Microsoft 365), you consume a complete application delivered over the internet. The provider manages everything including the OS, middleware, and application. Customers only configure application settings and manage users/data governance. There is no capability to install an operating system in SaaS.
Incorrect. While IaaS allows OS installation, PaaS does not provide OS-level control. PaaS abstracts the OS away to reduce operational burden (patching, maintenance). Some PaaS offerings allow container deployment or runtime selection, which can confuse learners, but you still do not install/manage the underlying OS.
Incorrect. Neither PaaS nor SaaS allows you to install an operating system on the underlying service. PaaS focuses on application deployment without OS management, and SaaS provides a fully managed application. If OS installation is required, the correct model is IaaS.
