This MS-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 plans to migrate its on-premises workloads to the cloud. They will use Virtual Machines (VMs) for their legacy applications and a serverless computing service for new microservices. The cloud provider will manage the physical hardware, but the company is responsible for patching the operating system of the VMs. Which two cloud service models are being used?
IaaS and PaaS
VMs are IaaS; serverless is PaaS.
IaaS and SaaS
Why wrong: Serverless is not SaaS; SaaS is fully managed applications.
PaaS and SaaS
Why wrong: VMs are not PaaS.
IaaS only
Serverless is a different model.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
IaaS and PaaS
The company uses Virtual Machines (VMs) for legacy applications, where it manages the OS patching while the cloud provider handles the physical hardware — this is Infrastructure as a Service (IaaS). For new microservices, it uses a serverless computing service, which is a form of Platform as a Service (PaaS) where the provider manages the runtime and scaling, and the company only deploys code. Therefore, the two models are IaaS and PaaS, making option A correct.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Common exam traps
The trap here is that candidates confuse serverless computing with SaaS, thinking it is a fully managed software service, when in fact it is a PaaS model where the customer writes and deploys code, not consumes a pre-built application.
Detailed technical explanation
In IaaS, the provider manages the hypervisor and physical hosts (e.g., Azure Hyper-V), while the tenant is responsible for guest OS patching, application configuration, and security — this aligns with the shared responsibility model. Serverless computing, such as Azure Functions, runs code in a managed runtime (e.g., Node.js or .NET) on ephemeral containers, automatically scaling from zero; the provider handles OS updates, runtime patches, and infrastructure, which is a subset of PaaS. A subtle behavior: serverless can also be considered Functions-as-a-Service (FaaS), but in the MS-900 context, it falls under PaaS because it provides a platform for code execution without managing servers.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Describe cloud concepts — study guide chapter
Learn the concepts, then practise the questions
Describe cloud concepts practice questions
Targeted practice on this topic area only
All MS-900 questions
985 questions across all exam domains
Microsoft 365 Fundamentals MS-900 study guide
Full concept coverage aligned to exam objectives
MS-900 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise MS-900 questions linked to Describe Microsoft 365 apps and services.
Practise MS-900 questions linked to Describe Microsoft 365 pricing, licensing, and support.
Practise MS-900 questions linked to Describe cloud concepts.
Practise MS-900 questions linked to Describe security, compliance, privacy, and trust in Microsoft 365.
Practise MS-900 questions linked to Describe Microsoft 365 pricing and support.
Practise MS-900 questions linked to MS-900 fundamentals.
Practise MS-900 questions linked to MS-900 scenario.
Practise MS-900 questions linked to MS-900 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Describe cloud concepts — This question tests Describe cloud concepts — Read the scenario before looking for a memorised answer..
The correct answer is: IaaS and PaaS — The company uses Virtual Machines (VMs) for legacy applications, where it manages the OS patching while the cloud provider handles the physical hardware — this is Infrastructure as a Service (IaaS). For new microservices, it uses a serverless computing service, which is a form of Platform as a Service (PaaS) where the provider manages the runtime and scaling, and the company only deploys code. Therefore, the two models are IaaS and PaaS, making option A correct.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
About these practice questions
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 →
Keep practising
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.