An organization uses AWS Organizations with consolidated billing. The central IT team wants to allocate costs back to individual business units based on their resource usage. However, many resources like EC2 instances and S3 buckets are shared across business units. What is the MOST effective strategy to achieve accurate cost allocation?

Create separate AWS accounts for each business unit and migrate resources accordingly.

Implement a strict resource tagging strategy. Use AWS Cost Categories to group costs by business unit based on tags, and enable Cost and Usage Reports (CUR) for detailed analysis.

Use AWS Cost Explorer to manually filter costs by service and divide them equally among business units.

Enable AWS Compute Optimizer to identify which business unit is using which resource.