AWS Certified Solutions Architect - Professional (#99)

A large company has increased its utilization of AWS over time in an unmanaged way. As such, they have a large number of independent AWS accounts across different business units, projects, and environments. The company has created a Cloud Center of Excellence team, which is responsible for managing all aspects of the AWS Cloud, including their AWS accounts. Which of the following should the Cloud Center of Excellence team do to BEST address their requirements in a centralized way? (Choose two.)

Control all AWS account root user credentials. Assign AWS IAM users in the account of each user who needs to access AWS resources. Follow the policy of least privilege in assigning permissions to each user.
Tag all AWS resources with details about the business unit, project, and environment. Send all AWS Cost and Usage reports to a central Amazon S3 bucket, and use tools such as Amazon Athena and Amazon QuickSight to collect billing details by business unit.
Use the AWS Marketplace to choose and deploy a Cost Management tool. Tag all AWS resources with details about the business unit, project, and environment. Send all AWS Cost and Usage reports for the AWS accounts to this tool for analysis.
Set up AWS Organizations. Enable consolidated billing, and link all existing AWS accounts to a master billing account. Tag all AWS resources with details about the business unit, project and environment. Analyze Cost and Usage reports using tools such as Amazon Athena and Amazon QuickSight to collect billing details by business unit.
Using a master AWS account, create IAM users within the master account. Define IAM roles in the other AWS accounts, which cover each of the required functions in the account. Follow the policy of least privilege in assigning permissions to each role, then enable the IAM users to assume the roles that they need to use.