AZ-900 Describe Azure architecture and services 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.

• ✗

  Azure Custom Images from Compute Gallery

  Why it's wrong here

  Azure Custom Images from Compute Gallery (formerly Shared Image Gallery) are not correct because these are organization-created images that you define and share internally, usually built to capture your own patching, security, or application standards. A custom image starts from an existing base image (often a Marketplace image) and is then customized, generalized, and stored in an Azure Compute Gallery to be reused across subscriptions or regions. Because these are specific to your organization's environment and not a public, ready-to-deploy catalog, they do not provide the general pre-configured VM images referenced in the scenario — the Marketplace is the place to find those third-party and Microsoft-provided images.

• ✓

  Azure Marketplace VM images

  Why this is correct

  Azure Marketplace VM images are the correct choice because the Marketplace is Microsoft's curated online store of certified pre-configured virtual machine images, many of which bundle the OS and application stack (e.g., WordPress, SQL Server, or a custom ISV solution) so you deploy a full functional VM without manual installation. These images come from Microsoft, partners, and third-party vendors, are tested for compatibility, and allow you to provision a VM directly from the portal, CLI, or ARM templates. While user-uploaded custom images serve internal gold images, and container images serve containerized workloads, none match the Marketplace's broad catalog of turnkey VM images designed for instant VM deployment.

• ✗

  Azure DevTest Labs formulas

  Why it's wrong here

  Azure DevTest Labs formulas are not the right answer because they are not a source of pre-built images; instead, a formula is a lab configuration that lets you reuse settings, such as base VM image selection, virtual network size, and VM size, to create lab VMs consistently. Formulas abstract the provisioning parameters and act as an Azure Resource Manager (ARM) template layer on top of base images, which often come from the Marketplace or a custom image. The formula itself does not contain the OS or application binaries — it simply points to a base image and applies your team's standard configuration, making it a wrapper around images rather than a provider of pre-configured VM images.

• ✗

  Azure Container Registry base images

  Why it's wrong here

  Azure Container Registry base images are incorrect because Azure Container Registry (ACR) is a private registry for storing and managing container images in Docker or OCI format, intended for use by container orchestration platforms like Azure Kubernetes Service (AKS) or Azure Container Instances. A container image encapsulates an application and its dependencies in a portable runtime, but it is not a virtual machine image with a separate OS kernel, and it cannot be used directly to provision a traditional Azure VM. The scenario requires a VM image for deployment; while you could run containers on VMs, the container image itself is not the pre-configured VM image the question asks about.