A company hosts its order processing system on AWS. The architecture consists of afrontend and a backend. The frontend includes an Application Load Balancer (ALB) and Amazon EC2 instances in an Auto-Scaling group. The backend includes an EC2 instance and an Amazon RDS MySQL database. To prevent incomplete or lost orders, the company wants to ensure that order states are always preserved. The company wants to ensure that every order will eventually be processed, even after an outage or pause. Every order must be processed exactly once. Which solution will meet these requirements?