A company hosts a web application in a VPC on AWS. A public Application Load Balancer (ALB) forwards connections from the internet to an Auto Scaling group of Amazon EC2 instances. The Auto Scaling group runs in private subnets across four Availability Zones. The company stores data in an Amazon S3 bucket in the same Region. The EC2 instances use NAT gateways in each Availability Zone for outbound internet connectivity. The company wants to optimize costs for its AWS architecture. Which solution will meet this requirement?