The correct answer is that the file was detected as malware by Safe Attachments. Microsoft Defender for Office 365 Safe Attachments uses machine learning and detonation analysis to inspect files in SharePoint Online, and when a file is confirmed as malicious, it is automatically quarantined to prevent further access or spread. On the MS-102 exam, this question tests your understanding of how threat protection policies differ from other security controls—a common trap is confusing Data Loss Prevention (DLP) or retention policies with quarantine actions, but DLP only blocks sharing, not files, and retention policies preserve data without removing access. Remember that Safe Attachments is the only Defender feature that actively removes and isolates files based on malware detection. A helpful memory tip: “Safe Attachments = Safe Quarantine” — if a file is quarantined, think malware, not metadata or policy.
MS-102 Practice Question: Manage security and threats by using Microsoft Defender XDR
This MS-102 practice question tests your understanding of manage security and threats by using microsoft defender xdr. 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.
A user reports that they are unable to access a file in SharePoint Online. You check the audit log and see that the file was quarantined by Microsoft Defender for Office 365. What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The file was detected as malware by Safe Attachments.
Option C is correct because Defender for Office 365 can quarantine files that are detected as malicious by Safe Attachments. Option A is wrong because DLP policies block sharing, but do not quarantine files. Option B is wrong because retention policies do not quarantine. Option D is wrong because versioning does not cause quarantine. Option E is wrong because sensitivity labels classify, not quarantine.
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.
✗
The file was overwritten by a previous version.
Why it's wrong here
Versioning does not quarantine.
✓
The file was detected as malware by Safe Attachments.
Why this is correct
Safe Attachments quarantines malicious files.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The file has a retention policy that moved it to the Preservation Hold library.
Why it's wrong here
Retention policies preserve, not quarantine.
✗
The file was labeled as highly confidential by Microsoft Purview Information Protection.
Why it's wrong here
Labels do not quarantine.
✗
The file contains sensitive information and triggered a Data Loss Prevention (DLP) policy.
Why it's wrong here
DLP blocks sharing but does not quarantine files.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 MS-102 question in full detail.
Identify which MS-102 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Manage security and threats by using Microsoft Defender XDR — This question tests Manage security and threats by using Microsoft Defender XDR — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The file was detected as malware by Safe Attachments. — Option C is correct because Defender for Office 365 can quarantine files that are detected as malicious by Safe Attachments. Option A is wrong because DLP policies block sharing, but do not quarantine files. Option B is wrong because retention policies do not quarantine. Option D is wrong because versioning does not cause quarantine. Option E is wrong because sensitivity labels classify, not quarantine.
What should I do if I get this MS-102 question wrong?
Identify which MS-102 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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