The finance team needs to track past months' AWS cost and usage and automatically produce reports. Which AWS feature or service should they use to meet this requirement?

AWS Budgets allows you to set custom budgets to track your cost and usage from a specific start date. You can define alerts that notify you when your actual or forecasted costs exceed your budgeted amounts, and it can generate reports on past spending. This directly addresses the need to track past months' costs and automatically produce reports. Amazon Detective is a security service for investigating security findings. AWS Pricing Calculator helps estimate costs for new workloads, not track past usage. AWS Savings Plans offer discounted pricing in exchange for a commitment to a consistent amount of usage, but they don't provide cost tracking and reporting features themselves.