A company wants to change how internal cloud costs are reported to each business unit. The company uses AWS Organizations with a separate account per business unit and currently enforces tagging (application, environment, owner). They need a centralized, cost-effective solution that sends monthly cost reports to each business unit and notifies them when spending exceeds thresholds. What is the most cost-effective solution?

The correct solution leverages the centralized capabilities of AWS Organizations. Creating AWS Budgets and Cost Explorer reports in the management account allows for a single point of configuration and management for all business units, which is cost-effective and scalable. Budgets can be configured with filters (tags like application, environment, owner) to provide granular cost tracking and alerts. Subscribing business units to an SNS topic for alerts automates notifications. Incorrect options: Creating Budgets and using Cost Explorer in each account is less cost-effective and more complex to manage due to distributed configuration. Using the Billing and Cost Management dashboard in each account for reports is also decentralized and lacks the advanced reporting features of Cost Explorer. Enabling AWS Cost and Usage Reports (CUR) and using a Lambda function is a valid approach for highly customized reporting but is generally more complex and expensive to implement and maintain than using native AWS Budgets and Cost Explorer for this specific requirement.