AWS Cost Explorer is the correct service for visualizing, understanding, and managing AWS spending and usage over time. It provides:

• Interactive dashboards to visualize cost and usage data
• Time-based analysis to track spending patterns
• Cost forecasting to predict future expenses
• Resource-level granularity to identify specific cost drivers
• Customizable reports for different business needs

Why other options are incorrect:

• AWS Organizations: Manages multiple AWS accounts but doesn't focus on cost visualization
• AWS Pricing Calculator: Estimates costs before deployment but doesn't track actual spending
• AWS Service Catalog: Manages approved IT services but doesn't provide cost analysis features