Question 175 of 985

Describe cloud concepts →hardMultiple ChoiceObjective-mapped

What is SaaS in Cloud Computing for Microsoft 365?

This MS-900 practice question tests your understanding of describe cloud concepts. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

An organization uses Microsoft 365 E5 licenses. Users report that Microsoft 365 Apps for enterprise (e.g., Word, Excel) are slow to open. The IT team considers deploying a cloud-based solution to improve performance. Which cloud service model should they use?

A
Platform as a Service (PaaS)
Why wrong: PaaS is for developing and deploying custom applications, not for standard Office apps.
B
Software as a Service (SaaS)
SaaS delivers Microsoft 365 Apps via the cloud, optimized for performance and reduced local load.
C
Infrastructure as a Service (IaaS)
Why wrong: IaaS would require virtual machines and manual installation of Office, not improving performance directly.
D
Function as a Service (FaaS)
Why wrong: FaaS runs code in response to events, not relevant to Office performance.

Full breakdown with real-world context →

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

✓

Software as a Service (SaaS)

The organization is already using Microsoft 365 Apps for enterprise, which are delivered as a SaaS offering. To improve performance for slow-opening desktop apps, deploying a cloud-based solution means leveraging the same SaaS model—Microsoft 365 Apps are already SaaS. The issue is likely related to local installation or network latency, and using the web-based versions (also SaaS) or optimizing the existing SaaS delivery can help. Option B is correct because SaaS provides ready-to-use applications like Word and Excel via the cloud, eliminating local installation overhead.

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.

✗
Platform as a Service (PaaS)
Why it's wrong here
PaaS is for developing and deploying custom applications, not for standard Office apps.
✓
Software as a Service (SaaS)
Why this is correct
SaaS delivers Microsoft 365 Apps via the cloud, optimized for performance and reduced local load.
Related concept
Read the scenario before looking for a memorised answer.
✗
Infrastructure as a Service (IaaS)
Why it's wrong here
IaaS would require virtual machines and manual installation of Office, not improving performance directly.
✗
Function as a Service (FaaS)
Why it's wrong here
FaaS runs code in response to events, not relevant to Office performance.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates may confuse the need for a cloud-based solution with IaaS or PaaS, thinking they need to build or host the applications themselves, when the organization already has the SaaS solution (Microsoft 365) and just needs to optimize its delivery or use the web-based SaaS versions.

Detailed technical explanation

How to think about this question

Microsoft 365 Apps for enterprise are delivered via Click-to-Run streaming technology, which uses a virtualized file system and registry to minimize local footprint. Slow opening can be caused by large Office configuration cache files (e.g., OfficeC2RClient) or network latency to the Content Delivery Network (CDN) used for streaming. Switching to the web-based SaaS versions (Office for the web) bypasses local installation entirely, as they run in the browser and leverage server-side rendering, reducing client-side resource demands.

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 healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.

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: Software as a Service (SaaS) — The organization is already using Microsoft 365 Apps for enterprise, which are delivered as a SaaS offering. To improve performance for slow-opening desktop apps, deploying a cloud-based solution means leveraging the same SaaS model—Microsoft 365 Apps are already SaaS. The issue is likely related to local installation or network latency, and using the web-based versions (also SaaS) or optimizing the existing SaaS delivery can help. Option B is correct because SaaS provides ready-to-use applications like Word and Excel via the cloud, eliminating local installation overhead.

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.

About these practice questions

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Same concept, more angles

1 more ways this is tested on MS-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. Your organization uses Microsoft 365 and wants to provide employees with access to corporate resources from their personal devices without managing the entire device. Which cloud service model is being used?

easy

A.Infrastructure as a Service (IaaS)
B.Platform as a Service (PaaS)
C.Desktop as a Service (DaaS)
✓ D.Software as a Service (SaaS)

Why D: Software as a Service (SaaS) is the correct cloud service model because Microsoft 365 is a SaaS offering. Users access applications like Exchange Online, SharePoint, and Teams over the internet without managing the underlying infrastructure or the devices. IaaS provides virtual machines and storage, PaaS provides a platform for custom applications, and DaaS delivers virtual desktops, but none match the scenario of using corporate SaaS apps from personal devices without device management.

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