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.
A company has a VPC with public and private subnets in three Availability Zones. The company hosts a web application on Amazon EC2 instances in the private subnets. The instances need to download security patches from the internet but must not be directly accessible from the internet. Which solution meets these requirements with the least operational overhead?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "least"
Why it matters: You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Deploy a NAT gateway in each public subnet and configure the private subnet route tables to point to the respective NAT gateway.
Option D is correct because a NAT gateway is a fully managed AWS service that provides outbound internet connectivity for instances in private subnets while preventing inbound internet access. Deploying a NAT gateway in each public subnet across three Availability Zones ensures high availability and fault tolerance, and configuring private subnet route tables with a default route (0.0.0.0/0) pointing to the respective NAT gateway meets the requirement with minimal operational overhead, as AWS handles patching and scaling.
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 NAT instance in a public subnet and configure the private subnet route tables to point to the NAT instance.
Why it's wrong here
NAT instances require manual patching and failover.
✗
Attach an internet gateway to the VPC and add a default route to the internet gateway in the private subnet route tables.
Why it's wrong here
Private subnets would be directly accessible from the internet.
✗
Create a VPC endpoint for Amazon S3 and configure the instances to use the endpoint.
Why it's wrong here
VPC endpoints only provide access to AWS services, not general internet.
✓
Deploy a NAT gateway in each public subnet and configure the private subnet route tables to point to the respective NAT gateway.
The clue word "least" in the question point toward this answer.
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 distinction between managed NAT gateways and self-managed NAT instances, where candidates may choose the NAT instance option (A) due to lower cost, overlooking the 'least operational overhead' requirement, or they may incorrectly select the VPC endpoint option (C) thinking it provides general internet access.
Detailed technical explanation
How to think about this question
NAT gateways use Elastic IP addresses and perform source network address translation (SNAT) to translate private instance IPs to the NAT gateway's public IP for outbound traffic, while dropping unsolicited inbound traffic. Under the hood, NAT gateways are implemented as horizontally scaled, redundant devices within an Availability Zone, so deploying one per AZ ensures that if an AZ fails, instances in other AZs retain internet access. In a real-world scenario, a single NAT gateway in one AZ would become a single point of failure, causing private instances in other AZs to lose internet access if that AZ goes down.
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: Deploy a NAT gateway in each public subnet and configure the private subnet route tables to point to the respective NAT gateway. — Option D is correct because a NAT gateway is a fully managed AWS service that provides outbound internet connectivity for instances in private subnets while preventing inbound internet access. Deploying a NAT gateway in each public subnet across three Availability Zones ensures high availability and fault tolerance, and configuring private subnet route tables with a default route (0.0.0.0/0) pointing to the respective NAT gateway meets the requirement with minimal operational overhead, as AWS handles patching and scaling.
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.
Are there clue words in this question I should notice?
Yes — watch for: "least". You want the option with minimum overhead, fewest steps, or lowest impact — not the most feature-rich or comprehensive answer.
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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