In an attempt to cut costs, your accounts manager has come to you and tells you that he thinks that if the company starts to use consolidated billing, it will save some money. He also wants the billing set up in such a way that it is relatively simple, and it gives insights into each of the VPC environments regarding the utilization of the corresponding VPC resources. Which of the following setups would satisfy your account manager`s needs?

Answer options:

A.Use multiple VPC`s for the different departments ( eg: sales, marketing etc.) and tag the resources within the department.
B.Use one Payer Account and no linked accounts.
C.Use one Payer Account and many linked accounts.
D.IAM user access to the Billing and Cost Management console.

Answer – A and C
Each organization in AWS Organizations has a master account that pays the charges of all the member accounts. If you have access to the master account, you can see a combined view of the AWS charges incurred by the member accounts. 
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/consolidated-billing.html
We can have multiple VPC`s serving various departments, and we can use tags to define them and have one billing account. The tags associated with the VPC`s will distinguish each department or environment.
Option A is CORRECT because VPC helps you segregate and organize your resources as per the functionality or domain, thus enabling the account owner to get insight into the resources` costing within the logical grouping of the resources. e.g., If an organization has a separate VPC for each department - Finance, Development, Sales etc. It will be convenient to get the billing details per department.
Option B is incorrect because if all the resources are created under a single account, it will be difficult for the accounts manager to get insights into the utilization of resources as per the domains or functionality. e.g., Instead of having a separate department such as Finance, Development, Sales, etc., if an organization has a single account, it will be tedious to get the details on the billing of each departmental resource.
Option C is CORRECT as having a linked account would enable the accounts manager to leverage the Consolidated Billing for multiple AWS accounts. With Consolidated Billing, you can see a combined view of AWS charges incurred by all accounts, as well as get a cost report for each account associated with your payer account.
Option D is INCORRECT because only IAM User access will not be sufficient for Consolidated Billing.
For more information on consolidated billing, please refer to the below link-
http://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/consolidated-billing.html
You can also have the option of segregating the resources via multiple VPC’s and have the billing estimates done via each VPC.For more information on AWS VPC, please refer to the below link-
https://aws.amazon.com/vpc/