A three-tier web application used for employee training is accessed only 12 hours per day. The application stores data in an Amazon RDS for MySQL DB instance. The company wants to minimize costs. What should a solutions architect do?

The correct solution uses AWS Lambda and Amazon EventBridge to automate the starting and stopping of the Amazon RDS for MySQL DB instance. This directly addresses the cost-minimization requirement for a resource used only 12 hours per day, as RDS instances accrue charges even when idle. Lambda functions can be written to call the RDS API to start and stop the instance, and EventBridge (formerly CloudWatch Events) can schedule these Lambda invocations at specific times. Incorrect options: Configuring an IAM policy for AWS Systems Manager Session Manager is for secure shell access to instances, not for scheduling RDS instance start/stop. Creating an Amazon ElastiCache for Redis cluster would add cost and complexity, and wouldn't stop the RDS instance from running and incurring charges. Launching an Amazon EC2 instance to run a cron job is an unnecessary additional resource and cost, as serverless options like Lambda and EventBridge are more efficient for this task.