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?

Enable cross-zone load balancing so all targets receive traffic from every AZ.

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.

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.

NAT gateways affect egress to the internet; they do not control inter-AZ routing for load balancer traffic.

What does this SAA-C03 question test?

Static NAT maps one inside address to one outside address.

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. — Disabling cross-zone load balancing on an NLB can reduce inter-AZ data transfer by preventing unnecessary routing of traffic to targets in other AZs. This is cost-optimized when you already have healthy targets registered in each AZ and want clients to be handled locally as much as possible. Enabling cross-zone load balancing increases the chance of cross-AZ traffic, which often increases inter-AZ charges. Moving Regions or introducing NAT does not directly address the root cause (cross-AZ target selection behind the NLB). Why others are wrong: Enabling cross-zone load balancing is the opposite of the desired outcome because it increases how often traffic is spread across AZs, which can raise inter-AZ transfer charges. Moving to another Region may change where your service runs, but it does not inherently keep traffic within the same AZ, and it can introduce additional inter-Region transfer costs. NAT gateways do not control load balancer target routing between AZs, so they won’t fix inter-AZ charges from NLB traffic patterns.

What should I do if I get this SAA-C03 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.