A company has an AWS Organization with one account per department. Application teams deploy independently and the company wants to lower compute costs, manage costs across departments, and improve department-level billing visibility, without losing flexibility in selecting compute resources. Which solution meets these needs with minimal effort?

The two correct options address the core requirements. Using AWS Organizations to create a new organization, define an OU hierarchy, and invite/create accounts is foundational for centralized cost management and billing visibility across departments. This structure enables consolidated billing, which inherently lowers compute costs through volume discounts. Enabling all AWS Organizations features and implementing Service Control Policies (SCPs) further enhances this by allowing centralized control over maximum permissions, ensuring departments operate within defined guardrails without losing flexibility in their resource choices. SCPs can prevent the provisioning of overly expensive services, thus contributing to cost reduction and governance. The incorrect options fail to meet all requirements. Parameterized CloudFormation templates for IAM permissions don't directly address cost management or consolidated billing. Requiring each business unit to keep its own accounts with tagging and Cost Explorer provides some visibility but lacks the consolidated billing benefits and centralized governance of Organizations. Consolidating all workloads into a single account loses the departmental isolation and flexibility, and can introduce security and operational complexities that outweigh the tagging benefits.