Correct Answer: AThe best solution to meet the requirements with the least operational overhead is to enable Amazon GuardDuty and the Amazon RDS Protection feature. GuardDuty is a managed threat detection service that continuously monitors for malicious activity and unauthorized behavior, which eliminates the need for manual log analysis or custom scripts. By combining it with Amazon EventBridge and Amazon SNS, the setup becomes more straightforward and requires minimal ongoing maintenance. Other options involve higher levels of manual intervention or complex configurations, making them less desirable in terms of operational overhead.