- A
Disable cross-zone load balancing on the NLB so each client is routed to targets in the same AZ when possible.
Disabling cross-zone load balancing helps keep traffic within the same AZ, reducing inter-AZ data transfer charges.
- B
Enable cross-zone load balancing so all targets receive traffic from every AZ.
Why wrong: Enabling cross-zone generally increases cross-AZ traffic and can raise inter-AZ transfer costs.
- C
Move the NLB to a different Region so traffic is always kept local.
Why wrong: Changing Region does not eliminate inter-AZ traffic within the new Region and can add Region transfer costs.
- D
Replace the NLB with a NAT gateway to reduce data charges between AZs.
Why wrong: NAT gateways affect egress to the internet; they do not control inter-AZ routing for load balancer traffic.
Quick Answer
The answer is to disable cross-zone load balancing on the NLB. When cross-zone load balancing is enabled, each NLB node can distribute traffic to targets in any Availability Zone, which forces data to traverse AZ boundaries and incurs inter-AZ data transfer costs. By disabling this feature, each NLB node sends traffic only to targets within its own AZ, eliminating those cross-AZ charges while still routing only to healthy targets in that same AZ. On the SAA-C03 exam, this concept tests your understanding of how NLB node placement and target group configuration directly impact cost optimization. A common trap is assuming that distributing traffic across all AZs is always beneficial, but the exam emphasizes that cross-zone balancing is a paid feature for NLBs (unlike ALBs where it is free and enabled by default). Memory tip: think “NLB locks to local” — disabling cross-zone keeps traffic local to each AZ, saving costs.
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. 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 team runs an Amazon NLB in a VPC with targets registered in multiple Availability Zones (AZs). Their bill shows high inter-AZ data transfer charges. They want to reduce unnecessary cross-AZ traffic costs while still maintaining healthy targets per AZ. What change is most likely to reduce inter-AZ charges?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
Disable cross-zone load balancing on the NLB so each client is routed to targets in the same AZ when possible.
Option A is correct because disabling cross-zone load balancing on an NLB ensures that each client is routed only to targets within the same Availability Zone as the NLB node that receives the traffic. This eliminates inter-AZ data transfer charges because traffic never leaves the AZ boundary. The NLB still maintains healthy targets per AZ by distributing traffic only among healthy targets within that AZ.
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.
- ✓
Disable cross-zone load balancing on the NLB so each client is routed to targets in the same AZ when possible.
Why this is correct
Disabling cross-zone load balancing helps keep traffic within the same AZ, reducing inter-AZ data transfer charges.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Enable cross-zone load balancing so all targets receive traffic from every AZ.
Why it's wrong here
Enabling cross-zone generally increases cross-AZ traffic and can raise inter-AZ transfer costs.
- ✗
Move the NLB to a different Region so traffic is always kept local.
Why it's wrong here
Changing Region does not eliminate inter-AZ traffic within the new Region and can add Region transfer costs.
- ✗
Replace the NLB with a NAT gateway to reduce data charges between AZs.
Why it's wrong here
NAT gateways affect egress to the internet; they do not control inter-AZ routing for load balancer traffic.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume enabling cross-zone load balancing always reduces costs or improves performance, but for NLB it actually increases inter-AZ data transfer charges, and the question specifically asks for cost reduction, not high availability.
Detailed technical explanation
How to think about this question
By default, NLB cross-zone load balancing is disabled, meaning each NLB node only routes traffic to targets in its own AZ. When enabled, the NLB distributes traffic evenly across all registered targets in all AZs, which can improve fault tolerance but incurs inter-AZ data transfer costs (typically $0.01–$0.02 per GB). In a multi-AZ architecture, disabling cross-zone load balancing is a common cost-optimization strategy when per-AZ capacity is sufficient to handle the traffic, as it keeps traffic local to 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 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.
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FAQ
Questions learners often ask
What does this SAA-C03 question test?
Design Cost-Optimized Architectures — This question tests Design Cost-Optimized Architectures — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Disable cross-zone load balancing on the NLB so each client is routed to targets in the same AZ when possible. — Option A is correct because disabling cross-zone load balancing on an NLB ensures that each client is routed only to targets within the same Availability Zone as the NLB node that receives the traffic. This eliminates inter-AZ data transfer charges because traffic never leaves the AZ boundary. The NLB still maintains healthy targets per AZ by distributing traffic only among healthy targets within that AZ.
What should I do if I get this SAA-C03 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 SAA-C03 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 SAA-C03 exam.
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