What is the MOST cost-effective way for the company to avoid Regional data transfer charges?

A company runs a highly available image-processing application on Amazon EC2 instances in a single VPC. The EC2 instances run inside several subnets across multiple Availability Zones. The EC2 instances do not communicate with each other However, the EC2 instances download images from Amazon S3 and upload images to Amazon S3 through a single NAT gateway. The company is concerned about data transfer charges

What is the MOST cost-effective way for the company to avoid Regional data transfer charges?
A . Launch the NAT gateway in each Availability Zone
B. Replace the NAT gateway with a NAT instance
C. Deploy a gateway VPC endpoint for Amazon S3
D. Provision an EC2 Dedicated Host to run the EC2 instances

View Answer

Answer: A

Explanation:

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.

Reference: AWS NAT Gateway documentation:

https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html