A company has a three-tier application for image sharing. The application uses an Amazon EC2 instance for the front-end layer, another EC2 instance for the application layer, and a third EC2 instance for a MySQL database. A solutions architect must design a scalable and highly available solution that requires the least amount of change to the application. Which solution meets these requirements?

The correct solution provides scalability and high availability with minimal application changes. Elastic Beanstalk automates the deployment and scaling of web applications, making the front-end and application layers highly available across multiple Availability Zones (Multi-AZ) and load-balanced. Migrating the MySQL database to an Amazon RDS Multi-AZ DB instance ensures high availability and automatic failover for the database layer. Storing user images in Amazon S3 provides highly scalable, durable, and cost-effective object storage. The other options involve more significant application changes or do not fully address both scalability and high availability. For example, using Lambda and DynamoDB would require substantial re-architecting. Using an Auto Scaling group for the application layer is good, but hosting the front-end on S3 would require changes, and a memory-optimized instance type for the database doesn't inherently provide high availability.