Which AWS service of tool helps to centrally manage billing and allow controlled access to resources across AWS accounts?

Explanations:

AWS Identity and Access Management (IAM) is used for managing access to AWS services and resources, but it does not manage billing or account organization.

AWS Organizations allows you to manage billing and access control across multiple AWS accounts, making it the correct choice for centralized management.

Cost Explorer is a tool for visualizing and analyzing costs, but it does not provide account management or centralized billing capabilities.

AWS Budgets helps you set budgets for your AWS costs and usage, but it does not manage billing across multiple accounts or provide access controls.