The correct choice is to deploy a virtual machine scale set across multiple availability zones in a single region, as this configuration achieves the required 99.99% SLA for stateless VMs while minimizing costs. This works because Azure guarantees a 99.99% SLA when you run two or more instances across two or more availability zones within a region, and a VMSS inherently distributes instances across zones, providing both high availability and automatic scaling for stateless workloads. On the AZ-305 exam, this question tests your ability to match SLA tiers to Azure infrastructure—common traps include selecting an availability set (which only offers 99.95%) or opting for multi-region deployment (which adds unnecessary cost and complexity for a stateless app). Remember that for 99.99%, you need zone-level redundancy, not just fault domain separation. A quick memory tip: “Four nines means zones, not sets—scale sets across zones are your best bet.”
AZ-305 Design infrastructure solutions Practice Question
This AZ-305 practice question tests your understanding of design infrastructure 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 runs a critical application on Azure VMs in a single region. They need to improve availability to meet an SLA of 99.99% while minimizing costs. The application is stateless and can run on multiple VMs. Which solution should you recommend?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy a virtual machine scale set across multiple availability zones in a single region.
Option C is correct because a virtual machine scale set (VMSS) with zones across three availability zones provides 99.99% SLA and allows scaling. Option A is wrong because two VMs in an availability set provide only 99.95% SLA. Option B is wrong because two VMs in different regions adds cost and complexity. Option D is wrong because a single VM in a single zone offers no high availability.
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 a virtual machine scale set across multiple availability zones in a single region.
Why this is correct
VMSS with zones provides 99.99% SLA and cost-effective scaling.
Related concept
Read the scenario before looking for a memorised answer.
✗
Deploy two VMs in the same availability set in a single region.
Why it's wrong here
Availability set provides 99.95% SLA, not 99.99%.
✗
Deploy a single VM with Azure Site Recovery to another region.
Why it's wrong here
Single VM offers no high availability within the same region.
✗
Deploy two VMs in two different Azure regions with Azure Traffic Manager.
Why it's wrong here
Multi-region adds cost and complexity; SLA for single-region VMSS with zones meets 99.99%.
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 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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-305 question in full detail.
Identify which AZ-305 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.
Design infrastructure solutions — This question tests Design infrastructure solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Deploy a virtual machine scale set across multiple availability zones in a single region. — Option C is correct because a virtual machine scale set (VMSS) with zones across three availability zones provides 99.99% SLA and allows scaling. Option A is wrong because two VMs in an availability set provide only 99.95% SLA. Option B is wrong because two VMs in different regions adds cost and complexity. Option D is wrong because a single VM in a single zone offers no high availability.
What should I do if I get this AZ-305 question wrong?
Identify which AZ-305 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.
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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