A company plans to migrate its on-premises monolithic application to AWS, keeping as much front-end and back-end code as possible while breaking the system into smaller services that different teams will manage. The company needs a highly scalable solution that minimizes operational overhead. Which solution meets these requirements?

The correct answer is hosting the application on Amazon Elastic Container Service (Amazon ECS) with an Application Load Balancer. This approach allows the company to containerize its existing application, breaking it into smaller services (microservices) that different teams can manage, aligning with the requirement to keep existing code while modernizing. ECS provides high scalability and minimizes operational overhead compared to managing EC2 instances directly. The Application Load Balancer distributes traffic efficiently across the containerized services. Hosting on AWS Lambda is suitable for serverless functions, not typically for migrating monolithic applications while keeping significant front-end/back-end code. AWS Amplify is primarily for web and mobile front-end development, not the back-end services described. Hosting on Amazon EC2 instances with an Auto Scaling group offers scalability but involves more operational overhead for managing the underlying servers compared to ECS.