A company wants to track Amazon EC2 usage charges that are based on the value of a tag that is named Business-Unit. Company leaders instruct developers to update all EC2 resources with the tag. The developers notify the leaders that they have completed this task.
Later that week, a finance team member checks Cost Explorer. The finance team member sees EC2 costs in the different accounts but cannot find the Business-Unit tag to filter by or group by.
What is the MOST likely reason that the Business-Unit tag is absent?

A. The Business-Unit tag is not activated as a cost allocation tag in the AWS Billing and Cost Management console.
B. The Business-Unit tag is not valid because tag key names do not support dashes (-).
C. The instances have been rebooted, and the developers neglected to re-add the Business-Unit tag after the reboot.
D. The IAM user does not have permission to view the tags in Cost Explorer.