The answer is enabling all supported data sources and ensuring proper licensing, along with configuring automated investigation and response (AIR) for common incident types. These two practices are foundational because Microsoft Defender XDR deployment best practices for optimal detection and response rely on complete signal ingestion—every disabled data source creates a blind spot that undermines correlation across identities, endpoints, and cloud apps. AIR then operationalizes that data by using built-in playbooks to automatically triage and remediate high-volume alerts, directly reducing mean time to respond (MTTR) and freeing analysts for complex threats. On the Microsoft Cybersecurity Architect exam, this tests your understanding that XDR effectiveness is a function of both breadth (data sources) and automation (AIR), not just tool configuration. A common trap is assuming you can selectively enable sources to save costs, but the exam emphasizes that partial coverage breaks detection logic. Memory tip: think “Full Feed, Fast Action”—all signals in, automated playbooks out.
SC-100 Practice Question: Design solutions that align with security best practices and priorities
This SC-100 practice question tests your understanding of design solutions that align with security best practices and priorities. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which TWO are best practices for designing a Microsoft 365 Defender (XDR) deployment to ensure optimal detection and response?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "best"
Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure automated investigation and response for common incident types
B is correct because configuring automated investigation and response (AIR) for common incident types is a core best practice in Microsoft 365 Defender. AIR leverages built-in playbooks to automatically triage, investigate, and remediate alerts, reducing mean time to respond (MTTR) and allowing security teams to focus on complex threats. This aligns with the XDR principle of using automation to handle high-volume, predictable incidents efficiently.
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.
✗
Deploy Defender for Endpoint on unsupported operating systems with limited functionality
Why it's wrong here
Unsupported OS may not provide full telemetry.
✓
Configure automated investigation and response for common incident types
Why this is correct
Automation speeds up response and reduces workload.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Rely solely on manual alert triage to avoid missing complex attacks
Why it's wrong here
Manual triage is inefficient; automation helps.
✓
Enable all supported data sources and ensure proper licensing
Why this is correct
Complete data ingestion is critical for detection.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure each workload (Endpoint, Identity, etc.) in SILO mode to avoid false positives
Why it's wrong here
SILO mode reduces cross-product correlation.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may think enabling all data sources (option D) is unnecessary or could cause noise, but in XDR, comprehensive data ingestion is essential for accurate correlation and detection, while proper tuning and automation handle false positives.
Detailed technical explanation
How to think about this question
Under the hood, Microsoft 365 Defender’s automated investigation and response uses machine learning models and predefined playbooks that analyze signals from endpoints, identities, email, and cloud apps. For example, when a suspicious PowerShell command is detected on an endpoint, AIR can automatically isolate the device, block the command, and cross-reference user behavior analytics from Azure AD Identity Protection to determine if the activity is anomalous. This cross-workload correlation is what distinguishes XDR from siloed security tools.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this SC-100 question in full detail.
Design solutions that align with security best practices and priorities — This question tests Design solutions that align with security best practices and priorities — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Configure automated investigation and response for common incident types — B is correct because configuring automated investigation and response (AIR) for common incident types is a core best practice in Microsoft 365 Defender. AIR leverages built-in playbooks to automatically triage, investigate, and remediate alerts, reducing mean time to respond (MTTR) and allowing security teams to focus on complex threats. This aligns with the XDR principle of using automation to handle high-volume, predictable incidents efficiently.
What should I do if I get this SC-100 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: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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