AWS Organizations is the correct service for centrally managing multiple AWS accounts and using consolidated billing. Here's why:

• AWS Organizations: Allows you to create and manage multiple AWS accounts under a single organization, provides consolidated billing across all accounts, and enables policy-based management
• AWS Cost Explorer: A tool for analyzing and visualizing AWS costs and usage, but doesn't manage accounts or provide consolidated billing
• AWS Billing and Cost Management: Provides billing information and cost management features for individual accounts, but not centralized account management
• AWS Budgets: Helps set custom budgets and receive alerts when costs exceed thresholds, but doesn't manage multiple accounts

For a financial company needing to centrally manage multiple AWS accounts with consolidated billing, AWS Organizations is the appropriate solution.