A company is launching an application on AWS that uses an Application Load Balancer (ALB) to direct traffic to at least two Amazon EC2 instances in a single target group. Each environment uses an Auto Scaling group. The company requires both a development environment and a production environment; production will experience periods of high traffic. Which change configures the development environment MOST cost-effectively?

Reducing the maximum number of EC2 instances in the development environment's Auto Scaling group is the most cost-effective solution. This directly limits the number of instances that can launch, preventing unnecessary scaling during low-traffic periods common in development, thus saving compute costs. Reconfiguring the target group to have only one EC2 instance would work, but Auto Scaling groups are designed for dynamic scaling, and this approach bypasses that benefit. Changing the ALB balancing algorithm doesn't reduce costs; it only changes how traffic is distributed among existing instances. Reducing the size of EC2 instances in both environments might save some cost, but it's a less targeted approach for the development environment specifically and could impact performance in production.