A customer needs corporate IT governance and cost oversight of all AWS resources consumed by its divisions. The divisions want to maintain administrative control of the discrete AWS resources they consume and keep those resources separate from the resources of other divisions. How would you achieve this requirement?

Answer options:

A.Use AWS Organizations to manage AWS accounts, group the accounts into organizational units (OUs), and use the consolidated billing feature to consolidate billing and payment.
B.Create separate VPC`s for each division within the AWS account.
C.Write all child AWS CloudTrail and Cloudwatch logs to each child account`s Amazon S3 IA.D.Write all child AWS CloudTrail and Amazon CloudWatch logs to each child account`s Amazon S3 `Log` bucket.

Answers - A 
We need to satisfy 2 requirements here.
1. To provide either autonomy or control of divisions while maintaining IT Governance.
2. To evaluate the overall cost.
AWS Organizations enables you to consolidate multiple AWS accounts into an organization that you create and manage centrally. AWS Organizations also includes account management and consolidated billing capabilities.
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/consolidated-billing.html
https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_org_support-all-features.html
Options B, C, and D do not satisfy the requirements of the scenario mentioned in the question.
For more details, please check below AWS Docs.
https://aws.amazon.com/blogs/aws/aws-organizations-policy-based-management-for-multiple-aws-accounts/