- A
Software as a Service (SaaS)
Why wrong: Incorrect. In SaaS, the provider manages the entire application stack, including the OS and application, and the customer only accesses the software.
- B
Platform as a Service (PaaS)
Why wrong: Incorrect. In PaaS, the provider manages the underlying infrastructure and the runtime environment (including OS patching), and the customer focuses on deploying applications.
- C
Infrastructure as a Service (IaaS)
Correct. The customer has control over the OS, storage, and deployed applications, while the provider manages the physical infrastructure.
- D
Function as a Service (FaaS)
Why wrong: Incorrect. FaaS is a subset of serverless computing where the customer uploads code functions and the provider handles all infrastructure, including the OS.
MS-900 Describe cloud concepts Practice Question
This MS-900 practice question tests your understanding of describe cloud concepts. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 runs a custom application on a cloud provider's infrastructure. The provider manages the physical servers, networking, and storage, but the company installs, configures, and patches the operating system and application. Which cloud service model is this?
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
Infrastructure as a Service (IaaS)
This scenario describes Infrastructure as a Service (IaaS) because the cloud provider manages the underlying physical infrastructure (servers, networking, storage), while the customer retains control over the operating system, middleware, and application. In IaaS, the customer is responsible for OS patching, configuration, and application management, which matches the given responsibilities.
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.
- ✗
Software as a Service (SaaS)
Why it's wrong here
Incorrect. In SaaS, the provider manages the entire application stack, including the OS and application, and the customer only accesses the software.
- ✗
Platform as a Service (PaaS)
Why it's wrong here
Incorrect. In PaaS, the provider manages the underlying infrastructure and the runtime environment (including OS patching), and the customer focuses on deploying applications.
- ✓
Infrastructure as a Service (IaaS)
Why this is correct
Correct. The customer has control over the OS, storage, and deployed applications, while the provider manages the physical infrastructure.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Function as a Service (FaaS)
Why it's wrong here
Incorrect. FaaS is a subset of serverless computing where the customer uploads code functions and the provider handles all infrastructure, including the OS.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is confusing IaaS with PaaS because both involve deploying applications, but the key differentiator is OS-level control and patching responsibility—IaaS gives you full OS access, while PaaS abstracts it away.
Detailed technical explanation
How to think about this question
Under the hood, IaaS delivers virtualized compute resources via hypervisors (e.g., Hyper-V, KVM) and APIs for provisioning VMs, storage, and virtual networks. The customer interacts with the OS kernel (e.g., via SSH or RDP) to apply security patches, configure firewalls, and manage applications, while the provider handles hardware redundancy and physical security. A real-world example is running a custom .NET application on an Azure VM, where you must install Windows Server updates and configure IIS yourself.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this MS-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: Infrastructure as a Service (IaaS) — This scenario describes Infrastructure as a Service (IaaS) because the cloud provider manages the underlying physical infrastructure (servers, networking, storage), while the customer retains control over the operating system, middleware, and application. In IaaS, the customer is responsible for OS patching, configuration, and application management, which matches the given responsibilities.
What should I do if I get this MS-900 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
This MS-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 MS-900 exam.
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