- A
Elasticity
Why wrong: Elasticity is the ability to automatically scale resources up or down based on demand, not the ability to withstand component failures without interruption.
- B
Fault tolerance
Fault tolerance means the system continues to operate correctly even when a component fails. The application's design to run without interruption when an entire availability zone fails is a direct example of fault tolerance.
- C
High availability
Why wrong: High availability focuses on minimizing downtime but typically allows for a short period of unavailability during failover (e.g., seconds to minutes). The scenario specifies 'without any interruption,' which is a stricter requirement more aligned with fault tolerance.
- D
Scalability
Why wrong: Scalability is the ability to handle growing workloads by adding resources, not the ability to maintain operation during component failures.
Quick Answer
The answer is fault tolerance. This is correct because fault tolerance is the cloud computing characteristic that ensures a system continues operating without any interruption when a component fails, such as an entire availability zone. In this scenario, deploying the application across three Azure availability zones guarantees zero downtime even if one zone is lost, which is the defining trait of fault tolerance rather than high availability, which allows for brief downtime or failover delays. On the Microsoft Azure Fundamentals AZ-900 exam, this distinction is a common trap: high availability focuses on minimizing downtime (e.g., 99.99% uptime), while fault tolerance demands absolute continuity with no interruption. A helpful memory tip is to think of fault tolerance as “no tolerance for failure”—the system keeps running seamlessly, whereas high availability might still require a short recovery window.
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 deploys a mission-critical application across three Azure availability zones. The application is designed to continue operating without any interruption if an entire availability zone becomes unavailable. Which cloud computing characteristic does this scenario best illustrate?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"best"Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
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
Fault tolerance
B is correct because fault tolerance is the ability of a system to continue operating without any interruption when a component fails. Deploying a mission-critical application across three Azure availability zones ensures that if an entire zone goes down, the application remains operational with zero downtime, which is the defining characteristic of fault tolerance.
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.
- ✗
Elasticity
Why it's wrong here
Elasticity is the ability to automatically scale resources up or down based on demand, not the ability to withstand component failures without interruption.
- ✓
Fault tolerance
Why this is correct
Fault tolerance means the system continues to operate correctly even when a component fails. The application's design to run without interruption when an entire availability zone fails is a direct example of fault tolerance.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
High availability
Why it's wrong here
High availability focuses on minimizing downtime but typically allows for a short period of unavailability during failover (e.g., seconds to minutes). The scenario specifies 'without any interruption,' which is a stricter requirement more aligned with fault tolerance.
- ✗
Scalability
Why it's wrong here
Scalability is the ability to handle growing workloads by adding resources, not the ability to maintain operation during component failures.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse high availability with fault tolerance, but high availability allows for brief downtime during failover (e.g., 99.99% uptime), while fault tolerance guarantees zero interruption even during a complete zone failure.
Trap categories for this question
Scenario analysis trap
High availability focuses on minimizing downtime but typically allows for a short period of unavailability during failover (e.g., seconds to minutes). The scenario specifies 'without any interruption,' which is a stricter requirement more aligned with fault tolerance.
Detailed technical explanation
How to think about this question
Fault tolerance in Azure is achieved through redundancy at the infrastructure level, such as using Availability Zones that are physically separate datacenters within a region, each with independent power, cooling, and networking. Under the hood, Azure uses load balancers and traffic manager to automatically route requests away from a failed zone, ensuring zero data loss and no interruption. In a real-world scenario, a banking application using Azure SQL Database with zone-redundant configuration can survive a full zone outage without any transaction loss.
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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this AZ-900 question test?
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: Fault tolerance — B is correct because fault tolerance is the ability of a system to continue operating without any interruption when a component fails. Deploying a mission-critical application across three Azure availability zones ensures that if an entire zone goes down, the application remains operational with zero downtime, which is the defining characteristic of fault tolerance.
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.
Are there clue words in this question I should notice?
Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 11, 2026
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.
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