An organization has 10 departments. The organization wants to track the AWS usage of each department. Which of the
below mentioned options meets the requirement?

A.
Setup IAM groups for each department and track their usage

B.
Create separate accounts for each department, but use consolidated billing for payment and tracking

C.
Create separate accounts for each department and track them separately

D.
Setup IAM users for each department and track their usage

Explanation:
The cost of an IAM user or groups can never be tracked separately for the purpose of billing. The best solution in this
case is to create a separate account for each department and use consolidated billing.
http://docs.aws.amazon.com/IAM/latest/UserGuide/IAM_Introduction.html