AZ-900 Practice Question 31: IaaS Use Case

IaaS is the most flexible cloud service category and gives you the maximum amount of control. The provider is responsible for maintaining the hardware, network connectivity to the internet, and physical security; you are responsible for everything else, including operating system installation, configuration, and maintenance. Microsoft's first listed IaaS scenario is exactly this one, lift-and-shift migration, where you set up cloud resources similar to your on-premises datacenter and then move the workloads across untouched.

Option B describes PaaS correctly but not the requirement: handing the operating system to Microsoft means the existing agents and configuration cannot come along unchanged. Option C describes SaaS correctly, and it is not a migration at all; replacing 200 servers with a subscription to someone else's finished application is a re-purchase of the business capability. Option D names the right service type but reverses the split; the provider never hands you the physical hardware, and in IaaS your applications are emphatically your own problem.

Reference: Describe Infrastructure as a Service