SAA-C03 Design Cost-Optimized Architectures Practice Question
This SAA-C03 practice question tests your understanding of design cost-optimized architectures. 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. A key principle to apply: nAT Gateways provide outbound internet access for private subnets.. 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 dev sandbox currently uses two NAT gateways in each of three Availability Zones, but only one private subnet per AZ needs outbound internet access. What should the architect review first? The design must avoid adding custom operational scripts.
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Whether one NAT gateway per AZ is sufficient for the required private subnets
Option D is correct because the question asks what the architect should review first to optimize costs while maintaining functionality. Using two NAT gateways per AZ when only one private subnet per AZ needs outbound internet access is redundant; a single NAT gateway per AZ can handle the traffic for all private subnets in that AZ. The design must avoid custom operational scripts, so the simplest review is to check if one NAT gateway per AZ is sufficient, which would reduce costs without breaking connectivity.
Key principle: NAT Gateways provide outbound internet access for private subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Disabling route tables
Why it's wrong here
Route tables are required for subnet routing.
✗
Replacing every NAT gateway with an internet gateway attached to private subnets
Why it's wrong here
Private subnets cannot use an internet gateway directly without public IP routing.
✗
Moving all workloads to public subnets
Why it's wrong here
This weakens security posture and is not a cost-first best practice.
✓
Whether one NAT gateway per AZ is sufficient for the required private subnets
Why this is correct
NAT gateways are normally deployed per AZ for resilience; duplicate NAT gateways in the same AZ may be unnecessary.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
NAT Gateways provide outbound internet access for private subnets.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may assume more NAT gateways are always better for high availability, but the question asks for a cost-optimization review first, and the current setup is over-provisioned for the stated requirement.
Detailed technical explanation
How to think about this question
NAT gateways are charged per hour and per gigabyte of data processed; using two per AZ doubles the hourly cost even if one is idle. AWS allows multiple private subnets in the same AZ to share a single NAT gateway via the same route table entry (0.0.0.0/0 pointing to the NAT gateway ID). In a real-world scenario, if the single NAT gateway becomes a bottleneck, you can scale by increasing its size or adding a second, but that should be reviewed after confirming the baseline need.
KKey Concepts to Remember
NAT Gateways provide outbound internet access for private subnets.
AWS recommends one NAT Gateway per Availability Zone for high availability.
A single NAT Gateway can serve multiple private subnets within the same AZ.
NAT Gateways are provisioned per AZ and incur hourly charges plus data processing fees.
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
NAT Gateways provide outbound internet access for private subnets.
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.
What to study next
Got this wrong? Here's your next step.
Review nAT Gateways provide outbound internet access for private subnets., then practise related SAA-C03 questions on the same topic to reinforce the concept.
Design Cost-Optimized Architectures — This question tests Design Cost-Optimized Architectures — NAT Gateways provide outbound internet access for private subnets..
What is the correct answer to this question?
The correct answer is: Whether one NAT gateway per AZ is sufficient for the required private subnets — Option D is correct because the question asks what the architect should review first to optimize costs while maintaining functionality. Using two NAT gateways per AZ when only one private subnet per AZ needs outbound internet access is redundant; a single NAT gateway per AZ can handle the traffic for all private subnets in that AZ. The design must avoid custom operational scripts, so the simplest review is to check if one NAT gateway per AZ is sufficient, which would reduce costs without breaking connectivity.
What should I do if I get this SAA-C03 question wrong?
Review nAT Gateways provide outbound internet access for private subnets., then practise related SAA-C03 questions on the same topic to reinforce the concept.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
NAT Gateways provide outbound internet access for private subnets.
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