The correct answer is immutable blob storage with a time-based retention policy. This Azure feature enforces WORM (Write Once, Read Many) compliance, locking data at the blob level so it cannot be modified or deleted for a specified period—exactly the 7-year regulatory requirement for sensitive transaction records. Even administrators with elevated permissions cannot bypass this lock, making it the only option that guarantees immutability for compliance. On the AZ-305 exam, this scenario tests your ability to distinguish between time-based and legal hold policies; a common trap is choosing a retention policy on a storage account or container level, which does not enforce true immutability. Remember the mnemonic “WORM for Time, Hold for Court”—time-based policies lock data for a fixed duration, while legal holds are indefinite and used for litigation.
AZ-305 Design data storage solutions Practice Question
This AZ-305 practice question tests your understanding of design data storage solutions. 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.
A financial services company needs to store sensitive transaction records in Azure for 7 years to meet regulatory compliance. The data must be immutable and cannot be deleted or modified during the retention period. Which Azure storage feature should you enable?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Immutable blob with time-based retention policy
Option C is correct because immutable blob storage with a time-based retention policy enforces WORM (Write Once, Read Many) compliance, ensuring that data cannot be deleted or modified for a specified retention period. This meets the 7-year regulatory requirement for sensitive transaction records, as the policy locks the data at the blob level and prevents any overwrite or deletion, even by administrators with elevated permissions.
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.
✗
Blob versioning with lifecycle management
Why it's wrong here
Versioning does not prevent deletion of specific versions; lifecycle management can delete old versions.
✗
Soft delete for blob storage
Why it's wrong here
Soft delete allows recovery but does not prevent deletion during retention.
✓
Immutable blob with time-based retention policy
Why this is correct
Immutable blob policies guarantee data cannot be deleted or modified for a specified period.
Related concept
Read the scenario before looking for a memorised answer.
✗
Legal hold on the storage container
Why it's wrong here
Legal hold is for indefinite hold and not for a fixed retention period.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse soft delete or versioning with immutability, not realizing that only immutable blob storage provides true WORM protection that prevents any modification or deletion during the retention period.
Detailed technical explanation
How to think about this question
Immutable blob storage uses a time-based retention policy that locks the blob at the storage account level, leveraging Azure's WORM implementation. Under the hood, the policy sets a retention interval in seconds (minimum 1 day) and applies a 'retention until' date; once set, the blob cannot be deleted or overwritten until that date, even by the storage account owner. A real-world scenario where this matters is in financial audits, where regulators require proof that records were not tampered with during the retention period, and the policy must be enabled before any data is written to the container.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-305 question in full detail.
Design data storage solutions — This question tests Design data storage solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Immutable blob with time-based retention policy — Option C is correct because immutable blob storage with a time-based retention policy enforces WORM (Write Once, Read Many) compliance, ensuring that data cannot be deleted or modified for a specified retention period. This meets the 7-year regulatory requirement for sensitive transaction records, as the policy locks the data at the blob level and prevents any overwrite or deletion, even by administrators with elevated permissions.
What should I do if I get this AZ-305 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
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 →
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. A financial services company needs to store transaction logs for regulatory compliance. The logs must be stored in a cost-effective manner, and they must be immutable to prevent tampering. The logs are accessed infrequently but must be retained for 7 years. Which Azure storage solution should you recommend?
medium
A.Azure Cosmos DB with time-to-live (TTL)
✓ B.Azure Blob Storage with immutable storage policy and cool access tier
C.Azure SQL Database with long-term retention backup
D.Azure Files with share snapshots
Why B: Azure Blob Storage with an immutable storage policy (WORM) ensures that transaction logs cannot be modified or deleted during the retention period, meeting compliance requirements. The cool access tier is cost-effective for infrequently accessed data, and the 7-year retention aligns with the policy's time-based retention. This combination provides both immutability and low-cost storage for long-term archival.
Last reviewed: Jun 24, 2026
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.
This AZ-305 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 AZ-305 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.