A medical records company runs an application on Amazon EC2 instances in public subnets that processes files stored in Amazon S3. The EC2 instances access Amazon S3 over the internet and do not require any other network access. A new requirement mandates that file-transfer network traffic use a private route and not traverse the internet. Which network architecture change meets this requirement?

The correct solution involves moving the EC2 instances to private subnets and using a VPC endpoint for Amazon S3. A VPC endpoint provides a private connection between your VPC and supported AWS services, ensuring that traffic between your EC2 instances and S3 does not traverse the internet. This directly meets the requirement for a private route for file-transfer network traffic. Creating a NAT gateway would still route traffic over the internet, as NAT gateways are used to allow instances in private subnets to initiate outbound connections to the internet. Configuring security groups only restricts traffic; it doesn't change the network path. Removing the internet gateway and using Direct Connect is an overly complex and expensive solution for this specific requirement, as Direct Connect is typically for connecting on-premises networks to AWS, not for private communication between AWS services within a VPC.