Reserved Instances are the correct choice because they offer the lowest cost for a predictable, uninterrupted workload like a nightly 4-hour batch job. This pricing model provides a significant discount—up to 72% compared to Pay-as-You-Go—in exchange for a 1- or 3-year commitment, making it ideal for steady-state usage where the resource runs consistently over time. On the Microsoft Azure Fundamentals AZ-900 exam, this scenario tests your understanding of how reserved instances pricing aligns with workload patterns: the key is recognizing that “cannot be interrupted” and “runs every night” signal a predictable, long-term need, not a spot or short-term burst. A common trap is choosing Spot VMs for cost savings, but those can be evicted, which fails the “cannot be interrupted” requirement. Memory tip: think “Reserved for Routine”—if the job is regular and reliable, reserve it for the deepest discount.
AZ-900 Describe cloud concepts Practice Question
This AZ-900 practice question tests your understanding of describe cloud concepts. 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 company runs a batch job every night that takes 4 hours and cannot be interrupted. Which VM pricing model provides the lowest cost for this workload?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Reserved Instances (1 or 3-year)
Reserved Instances (RIs) provide the lowest cost for a predictable, uninterrupted workload like a nightly 4-hour batch job because they offer a significant discount (up to 72% vs. Pay-as-you-Go) in exchange for a 1- or 3-year commitment. Since the job runs every night and cannot be interrupted, the workload is steady and predictable, making RIs the most cost-effective choice despite the upfront commitment.
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.
✗
Spot VMs
Why it's wrong here
Spot VMs can be interrupted at any time, making them unsuitable for workloads that cannot be interrupted.
✓
Reserved Instances (1 or 3-year)
Why this is correct
Reserved Instances provide up to 72% discount and are never interrupted — ideal for scheduled non-interruptible workloads.
Related concept
Read the scenario before looking for a memorised answer.
✗
Pay-as-you-Go Instances
Why it's wrong here
Pay-as-you-go has no discount; Reserved Instances provide significant savings for predictable usage.
✗
Dedicated Hosts
Why it's wrong here
Dedicated Hosts provide physical isolation at higher cost — not the right choice for cost optimization.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose Spot VMs for cost savings without recognizing the 'cannot be interrupted' requirement, which directly contradicts Spot's eviction policy, or they overlook that Reserved Instances provide the lowest cost for predictable, steady-state workloads even if the VM runs only part of the day.
Detailed technical explanation
How to think about this question
Reserved Instances apply a billing discount to the underlying VM compute cost, not the VM itself, and are scoped to a region or availability zone. For a nightly 4-hour job, you can use a single VM with a 1-year RI, which bills at the discounted rate for every hour of the day, even when the VM is deallocated, as long as the RI is active. This makes RIs ideal for workloads with consistent baseline usage, as the discount applies regardless of actual runtime, provided the VM size and region match the reservation.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-900 question in full detail.
Describe cloud concepts — This question tests Describe cloud concepts — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Reserved Instances (1 or 3-year) — Reserved Instances (RIs) provide the lowest cost for a predictable, uninterrupted workload like a nightly 4-hour batch job because they offer a significant discount (up to 72% vs. Pay-as-you-Go) in exchange for a 1- or 3-year commitment. Since the job runs every night and cannot be interrupted, the workload is steady and predictable, making RIs the most cost-effective choice despite the upfront commitment.
What should I do if I get this AZ-900 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 →
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-900 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-900 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.