Answer - B.
You can use the Consolidated Billing feature to consolidate payment for multiple Amazon Web Services (AWS) accounts or multiple Amazon International Services Pvt.
Ltd (AISPL) accounts within your organization by designating one of them to be the payer account.
For billing purposes, the consolidated billing feature of AWS Organizations treats all the accounts in the organization as one account.
This means that all accounts in the organization can receive the hourly cost-benefit of Reserved Instances that are purchased by any other account.
Option A is incorrect because combined billing is itself the functionality of Consolidated billing.
Options C and D are just the distractors.