The correct answer is B, AWS Organizations. AWS Organizations is designed to consolidate multiple AWS accounts into a single organization, allowing for centralized management of policies, security, and billing. This service is ideal for a company that has acquired others and needs to manage all accounts from a single point. AWS Systems Manager (A) is used for managing AWS infrastructure, not for account management. AWS Security Hub (C) focuses on providing a comprehensive view of security across AWS accounts, but it does not centralize account management. Amazon Workspaces (D) is a fully managed, secure Desktop-as-a-Service (DaaS) solution and is not related to account management.