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 wants to reduce hardware maintenance costs by moving to the cloud. They need to maintain full control over the operating system, applications, and security configurations, but do not want to manage physical servers or data center facilities. Which cloud service model should they choose?
Why wrong: SaaS provides ready-to-use applications hosted by the provider; the user does not control the operating system or underlying infrastructure.
B
Platform as a Service (PaaS)
Why wrong: PaaS offers a runtime environment for developing and deploying applications. The provider manages the OS, limiting user control over the OS and configurations.
C
Infrastructure as a Service (IaaS)
IaaS gives the user control over the operating system, applications, and security configurations while the cloud provider manages the physical hardware.
D
On-premises
Why wrong: On-premises is not a cloud service model; it involves managing all hardware and software locally, which does not reduce hardware maintenance costs.
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)
Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, allowing the company to deploy and manage their own operating systems, applications, and security configurations while offloading the physical hardware and data center management to the cloud provider. This model gives the highest level of control over the software stack without the burden of maintaining physical servers, aligning perfectly with the requirement to reduce hardware maintenance costs while retaining full administrative access.
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
SaaS provides ready-to-use applications hosted by the provider; the user does not control the operating system or underlying infrastructure.
✗
Platform as a Service (PaaS)
Why it's wrong here
PaaS offers a runtime environment for developing and deploying applications. The provider manages the OS, limiting user control over the OS and configurations.
✓
Infrastructure as a Service (IaaS)
Why this is correct
IaaS gives the user control over the operating system, applications, and security configurations while the cloud provider manages the physical hardware.
Related concept
Read the scenario before looking for a memorised answer.
✗
On-premises
Why it's wrong here
On-premises is not a cloud service model; it involves managing all hardware and software locally, which does not reduce hardware maintenance costs.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse PaaS with IaaS because both are cloud models, but PaaS removes control over the OS and runtime environment, which is the critical distinction when the question explicitly requires maintaining full control over the operating system and security configurations.
Detailed technical explanation
How to think about this question
Under the hood, IaaS delivers virtual machines (VMs) via hypervisors such as VMware ESXi or Microsoft Hyper-V, with the cloud provider managing the physical host, storage, and networking. The customer retains full administrative access to the VM via Remote Desktop Protocol (RDP) or Secure Shell (SSH), enabling them to install custom OS patches, configure Group Policy Objects, and deploy third-party security tools like antivirus or intrusion detection systems. In a real-world scenario, a company migrating legacy line-of-business applications that require specific Windows Server features and custom firewall rules would choose IaaS to avoid refactoring the application while eliminating hardware refresh cycles.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this MS-900 question in full detail.
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) — Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, allowing the company to deploy and manage their own operating systems, applications, and security configurations while offloading the physical hardware and data center management to the cloud provider. This model gives the highest level of control over the software stack without the burden of maintaining physical servers, aligning perfectly with the requirement to reduce hardware maintenance costs while retaining full administrative access.
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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