After a merger, the company has multiple existing AWS accounts for different business units. A central management account sent invitations to member accounts to join an AWS Organization. The solutions architect must enable centralized billing and centralized access policy management. What is the next step to allow the management account to manage member accounts?

To enable centralized management in AWS Organizations, the management account needs permission to access resources in member accounts. This is achieved by creating an IAM role, typically named OrganizationAccountAccessRole, in each member account. This role has a trust policy that allows the management account (specifically, the root user or an IAM role within the management account) to assume it. Assuming this role grants the management account the necessary permissions to manage the member account's resources. Creating an IAM group or policy directly in member accounts without a cross-account role assumption mechanism doesn't provide the management account with the necessary access. Creating a role in the management account and assigning it to administrators in member accounts is incorrect because roles are assumed by users or services, not assigned to other accounts for cross-account access in this manner.