A company is hosting their high-frequency trading application in AWS which serves millions of investors around the globe. The application is hosted in an Auto Scaling Group of EC2 instances behind an Application Load Balancer with an Amazon DynamoDB database. The architecture was deployed using a CloudFormation template with a Route 53 record. There recently was a production deployment that had caused system degradation and outage, costing the company a significant monetary loss due to their application's unavailability. As a result, the company instructed their DevOps engineer to implement an efficient strategy for deploying updates to their web application with the ability to perform an immediate rollback of the stack. All deployments should maintain the normal number of active EC2 instances to keep the performance of the application. Which of the following should the DevOps engineer implement to satisfy these requirements?