MS-900 Describe cloud concepts Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Software as a Service (SaaS)

  Why it's wrong here

  Software as a Service (SaaS) delivers fully managed applications accessed via a web browser, such as email or customer relationship management tools, where the provider handles everything from the physical data center to the application code. The customer only manages data and user settings, with no control over the underlying compute resources, operating system, or runtime environment. Because the question describes compute power as a service—raw resources like virtual machines—SaaS is not the correct category.

• ✗

  Platform as a Service (PaaS)

  Why it's wrong here

  Platform as a Service (PaaS) provides a managed platform for developing, testing, and running applications, including services like databases and middleware, but the compute nodes hosting that platform are abstracted away from the customer. Users deploy code without managing the operating system, server patches, or infrastructure, so while PaaS consumes compute power behind the scenes, it does not give customers direct access to virtual machines or storage as a service. This makes PaaS a layer above infrastructure, not the infrastructure-level compute service described.

• ✓

  Infrastructure as a Service (IaaS)

  Why this is correct

  Infrastructure as a Service (IaaS) supplies on-demand virtual machines, virtual networks, and block storage, giving the customer full administrative control over the guest operating system, applications, and security configurations. The provider operates the physical hosts, virtualization layer, and data center facilities, while the customer selects compute sizes, scales capacity, and manages the guest OS like a traditional server. This direct provisioning of compute power and storage is the definitive example of compute power as a service, unlike more abstracted models.

• ✗

  Function as a Service (FaaS)

  Why it's wrong here

  Function as a Service (FaaS) is a serverless execution model where the cloud provider runs individual functions in response to events, automatically allocating the necessary compute capacity and scaling it to zero when idle. The customer writes code without ever provisioning a server, seeing an operating system, or controlling the infrastructure, because the platform handles all of that invisibly. Although FaaS certainly uses compute power, it does not present compute power as a raw, user-manageable resource like IaaS does, so it is not the correct answer here.

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