A company plans to implement a monitoring system to track the cost-effectiveness of its Amazon EC2 resources across multiple AWS accounts. All existing resources are appropriately tagged to reflect the corresponding environment, department, and business unit for cost allocation purposes. The company has instructed its DevOps engineer to automate infrastructure cost optimization across various shared environments and accounts, including detecting EC2 instances with low utilization. Which is the MOST suitable solution that the DevOps engineer should implement in this scenario?