A company hosts an ecommerce application on a single Amazon RDS for MySQL DB instance. The company needs to mitigate the single point of failure with the LEAST implementation effort. Which solution meets this requirement?

Modifying the existing RDS DB instance to use a Multi-AZ deployment is the solution with the least implementation effort. This built-in RDS feature automatically provisions and maintains a synchronous standby replica in a different Availability Zone. In case of an infrastructure failure, RDS automatically fails over to the standby, minimizing downtime with no application changes required. The change can be applied during a maintenance window to avoid immediate impact. Migrating to DynamoDB (a NoSQL database) would require significant application re-architecture and data model changes, which is high effort. Creating a new Multi-AZ RDS instance and manually restoring from a snapshot is more effort than simply modifying the existing instance. Configuring a DB instance in an EC2 Auto Scaling group is not how RDS Multi-AZ works; RDS manages the high availability internally, and Auto Scaling groups are typically for EC2 instances, not RDS instances directly for this purpose.