- A
Applying security updates to the CRM application code.
Why wrong: Incorrect. The customer is responsible for managing and patching the application code because it is deployed and maintained by the customer on the virtual machine.
- B
Configuring firewall rules within the virtual network.
Why wrong: Incorrect. Customers manage network security configurations, such as network security group rules and firewall settings, for their virtual networks in IaaS.
- C
Replacing a failed physical hard disk drive in the Azure data center.
Correct. Microsoft manages the physical hardware in Azure data centers, including replacement of failed components like hard drives. This is part of the infrastructure responsibility.
- D
Installing the latest Windows Server security patches on the virtual machine.
Why wrong: Incorrect. Under IaaS, the customer is responsible for maintaining the operating system, including applying security patches, updates, and configuration management.
Quick Answer
The answer is replacing a failed physical hard disk drive in the Azure data center. This is correct because under the shared responsibility model for IaaS, Microsoft manages the physical infrastructure—including servers, storage, networking, and the data center itself—while the customer retains control over the operating system, applications, and data. In an IaaS deployment, you are responsible for everything you install or configure on the virtual machine, such as the Windows Server OS, the third-party database, and the CRM application, but you never have access to the underlying hardware. On the Microsoft Azure Fundamentals AZ-900 exam, this concept tests your understanding of where the responsibility boundary lies: the cloud provider handles the “physical” layer, and the customer handles the “logical” layer. A common trap is assuming Microsoft patches the guest OS or manages the database, but those are customer tasks in IaaS. Remember the memory tip: “Microsoft owns the floor and the walls; you own the furniture and the software inside the room.”
AZ-900 Describe cloud concepts Practice Question
This AZ-900 practice question tests your understanding of describe cloud concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is migrating a legacy customer relationship management (CRM) application to Azure infrastructure as a service (IaaS). The application runs on Windows Server and uses a third-party database. The company's IT team will manage the application and database software. However, they want to minimize their operational overhead for tasks that Azure can handle automatically. According to the shared responsibility model, which of the following tasks is the responsibility of Microsoft?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"minimum / minimize"Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Replacing a failed physical hard disk drive in the Azure data center.
In the shared responsibility model, Microsoft is responsible for the 'physical' aspects of the cloud, including the hardware, network, and data center infrastructure. Replacing a failed physical hard disk drive is a physical infrastructure task that falls under Microsoft's responsibility, as the customer has no access to the underlying hardware in an IaaS environment.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Applying security updates to the CRM application code.
Why it's wrong here
Incorrect. The customer is responsible for managing and patching the application code because it is deployed and maintained by the customer on the virtual machine.
- ✗
Configuring firewall rules within the virtual network.
- ✓
Replacing a failed physical hard disk drive in the Azure data center.
Why this is correct
Correct. Microsoft manages the physical hardware in Azure data centers, including replacement of failed components like hard drives. This is part of the infrastructure responsibility.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Installing the latest Windows Server security patches on the virtual machine.
Why it's wrong here
Incorrect. Under IaaS, the customer is responsible for maintaining the operating system, including applying security patches, updates, and configuration management.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'operational overhead' with 'security updates' or 'network configuration,' mistakenly thinking Azure handles all management tasks, but the shared responsibility model clearly separates physical infrastructure (Microsoft) from customer-managed software and configuration.
Detailed technical explanation
How to think about this question
Under the shared responsibility model for IaaS, Microsoft manages the physical host, storage, and networking infrastructure, including hardware replacement, power, and cooling. The customer retains control over the operating system, applications, and network configurations such as Network Security Groups (NSGs) and firewall rules. This distinction is critical in scenarios like hardware failures, where Azure automatically migrates the VM to healthy hardware, but the customer must still patch the OS and application.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this AZ-900 question test?
Describe cloud concepts — This question tests Describe cloud concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Replacing a failed physical hard disk drive in the Azure data center. — In the shared responsibility model, Microsoft is responsible for the 'physical' aspects of the cloud, including the hardware, network, and data center infrastructure. Replacing a failed physical hard disk drive is a physical infrastructure task that falls under Microsoft's responsibility, as the customer has no access to the underlying hardware in an IaaS environment.
What should I do if I get this AZ-900 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more ways this is tested on AZ-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company subscribes to a SaaS-based customer relationship management (CRM) application hosted in the cloud. The CRM provider manages the application, runtime, and infrastructure. The company's employees access the CRM via a web browser. According to the shared responsibility model, which security responsibility belongs solely to the company?
medium- A.Patching the underlying operating system of the CRM servers.
- B.Managing network access controls to the CRM application.
- ✓ C.Safeguarding the company's customer data and user identities.
- D.Ensuring physical security of the data centers hosting the CRM.
Why C: In a SaaS model, the provider manages the application, runtime, and infrastructure, including patching the OS and physical security. The customer retains responsibility for what they bring into the cloud: their data and user identities. Option C is correct because safeguarding customer data and managing user identities (e.g., via Azure AD) is solely the company's responsibility under the shared responsibility model.
Last reviewed: Jun 11, 2026
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.
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