A. Use AWS Config rules to define and detect resources that are not properly tagged.
B. Use Cost Explorer to display resources that are not properly tagged. Tag those resources manually.
C. Write API calls to check all resources for proper tag al__cpLocation. Periodically run the code on an EC2 instance.
D. Write API calls to check all resources for proper tag al__cpLocation. Schedule an AWS Lambda function through Amazon CloudWatch to periodically run the code.