A company runs a highly available image-processing application on Amazon EC2 instances in a single...

In this scenario, the company wants to avoid regional data transfer charges while downloading and uploading images from Amazon S3. To accomplish this at the lowest cost, the NAT gateway should be launched in each availability zone that the EC2 instances are running in. This allows the EC2 instances to route traffic through the local NAT gateway instead of sending traffic across an availability zone boundary and incurring regional data transfer fees. This method will help reduce the data transfer costs since inter-Availability Zone data transfers in a single region are free of charge.