The answer is to use NAT Gateways in public subnets for outbound internet access from private subnets, but this is only one of three critical factors; the foundational choice is deploying subnets across at least two Availability Zones (AZs). This ensures high availability by eliminating a single point of failure—if one AZ goes down, traffic shifts to the other, a core principle of fault-tolerant AWS architectures. For the ANS-C01 exam, this tests your grasp of multi-tier VPC design, where you must balance security layers (public, private, and database subnets) with redundancy. A common trap is focusing solely on NAT placement while forgetting that cross-AZ subnet distribution is the non-negotiable first step for high availability. Remember the memory tip: “AZs first, NATs second, security groups third” to prioritize fault tolerance over connectivity.
ANS-C01 Network Design Practice Question
This ANS-C01 practice question tests your understanding of network design. 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.
Which THREE factors should be considered when designing a VPC for a multi-tier application that requires high availability and security? (Choose three.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Provision subnets in at least two Availability Zones
Option A is correct because deploying subnets across at least two Availability Zones (AZs) ensures high availability by eliminating a single point of failure. If one AZ experiences an outage, the application can continue serving traffic from the other AZ. This is a foundational principle for building fault-tolerant architectures in AWS.
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.
✓
Provision subnets in at least two Availability Zones
Why this is correct
Provides high availability in case of AZ failure.
Related concept
Read the scenario before looking for a memorised answer.
✗
Assign public IP addresses to all instances for direct access
Use separate subnets for web, application, and database tiers
Why this is correct
Improves security through network segmentation.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a single Availability Zone to reduce latency
Why it's wrong here
Single AZ does not provide high availability.
✓
Use NAT Gateways in public subnets for outbound internet access from private subnets
Why this is correct
Allows private instances to reach the internet for updates.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
AWS often tests the misconception that high availability can be achieved within a single Availability Zone by using redundant components, but the correct approach requires at least two AZs to survive an AZ-level failure.
Detailed technical explanation
How to think about this question
When designing multi-tier applications, separate subnets for web, application, and database tiers (Option C) allow you to apply granular security group rules and network ACLs, restricting traffic flow between tiers. NAT Gateways (Option E) are highly available within an AZ and enable private subnet instances to initiate outbound internet connections (e.g., for software updates) while preventing inbound connections from the internet. Under the hood, NAT Gateways use Elastic IPs and are managed by AWS, automatically handling failover within the AZ.
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.
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.
Network Design — This question tests Network Design — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Provision subnets in at least two Availability Zones — Option A is correct because deploying subnets across at least two Availability Zones (AZs) ensures high availability by eliminating a single point of failure. If one AZ experiences an outage, the application can continue serving traffic from the other AZ. This is a foundational principle for building fault-tolerant architectures in AWS.
What should I do if I get this ANS-C01 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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This ANS-C01 practice question is part of Courseiva's free Amazon Web Services 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 ANS-C01 exam.
Question Discussion
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