Double the number of frontend and backend EC2 instances to handle the increased traffic during the product launch event. Create a dead-letter queue to retain unprocessed sales requests when the demand exceeds the system capacity.

Place the frontend EC2 instances into an Auto Scaling group. Create an Auto Scaling policy to launch new instances to handle the incoming network traffic.

Place the frontend EC2 instances into an Auto Scaling group. Add an Amazon ElastiCache cluster in front of the ALB to reduce the amount of traffic the API needs to handle.

Place the frontend and backend EC2 instances into separate Auto Scaling groups. Create a policy for the frontend Auto Scaling group to launch instances based on incoming network traffic. Create a policy for the backend Auto Scaling group to launch instances based on the SQS queue backlog.