- A
Azure Blob Storage with Hot tier and lifecycle management to Archive tier with WORM policy
Why wrong: While this can work, storing initially in Hot tier incurs unnecessary cost before lifecycle moves it. The question asks for lowest storage cost, so starting in Archive is cheaper.
- B
Azure Blob Storage with Cool tier and lifecycle management to Archive tier with legal hold
Why wrong: Legal hold applies to individual blobs and does not provide automated time-based retention. Also, Cool tier is more expensive than Archive.
- C
Azure Blob Storage with Archive tier and immutability policy (time-based retention)
Archive tier offers the lowest cost, and immutability policy ensures data cannot be deleted or modified during the 10-year retention.
- D
Azure Files with premium tier and soft delete
Why wrong: Azure Files is a file share service, not designed for archival storage. Premium tier is expensive, and soft delete does not provide immutability.
AZ-305 Design data storage solutions Practice Question
This AZ-305 practice question tests your understanding of design data storage solutions. 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 stores terabytes of archival data that must be retained for 10 years per regulatory requirements. The data is accessed infrequently (once or twice per year) and retrieval latency of up to 5 hours is acceptable. The company wants the lowest storage cost. They also need to ensure data is encrypted at rest and immutability to prevent deletion or modification during the retention period. Which Azure storage solution should they choose?
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
Azure Blob Storage with Archive tier and immutability policy (time-based retention)
Option C is correct because Azure Blob Storage's Archive tier offers the lowest storage cost for infrequently accessed data, and the immutability policy with time-based retention provides WORM (Write Once, Read Many) compliance to prevent deletion or modification for the required 10-year period. The 5-hour retrieval latency is acceptable for archival data accessed once or twice per year, and encryption at rest is automatically enabled for all Azure Blob Storage tiers.
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.
- ✗
Azure Blob Storage with Hot tier and lifecycle management to Archive tier with WORM policy
Why it's wrong here
While this can work, storing initially in Hot tier incurs unnecessary cost before lifecycle moves it. The question asks for lowest storage cost, so starting in Archive is cheaper.
- ✗
Azure Blob Storage with Cool tier and lifecycle management to Archive tier with legal hold
Why it's wrong here
Legal hold applies to individual blobs and does not provide automated time-based retention. Also, Cool tier is more expensive than Archive.
- ✓
Azure Blob Storage with Archive tier and immutability policy (time-based retention)
Why this is correct
Archive tier offers the lowest cost, and immutability policy ensures data cannot be deleted or modified during the 10-year retention.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Azure Files with premium tier and soft delete
Why it's wrong here
Azure Files is a file share service, not designed for archival storage. Premium tier is expensive, and soft delete does not provide immutability.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse legal hold (which is indefinite and does not prevent modification) with time-based retention immutability policy, or they incorrectly choose a higher-cost tier like Hot or Cool thinking lifecycle management will reduce costs, ignoring that the Archive tier itself is the cheapest and directly meets the latency requirement.
Detailed technical explanation
How to think about this question
Azure Blob Storage immutability policy uses time-based retention to enforce a WORM state for a specified duration (1 day to 146,000 days, covering 10 years), during which blobs cannot be deleted or overwritten by any user, including the storage account owner. The Archive tier has a 15-minute to 5-hour rehydration time for read access, and encryption at rest uses Azure Storage Service Encryption (SSE) with 256-bit AES, which is enabled by default and cannot be disabled.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this AZ-305 question test?
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: Azure Blob Storage with Archive tier and immutability policy (time-based retention) — Option C is correct because Azure Blob Storage's Archive tier offers the lowest storage cost for infrequently accessed data, and the immutability policy with time-based retention provides WORM (Write Once, Read Many) compliance to prevent deletion or modification for the required 10-year period. The 5-hour retrieval latency is acceptable for archival data accessed once or twice per year, and encryption at rest is automatically enabled for all Azure Blob Storage tiers.
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
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Last reviewed: Jun 11, 2026
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.
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