Correct Answer: B
AWS Trusted Advisor checks for service usage for all the resources within AWS Cloud and provides notifications.
Option A is incorrect as AWS Config can be used to audit, evaluate configurations of AWS resources. But it does not check service limits for resources.
Option C is incorrect as Amazon CloudWatch monitors AWS resources and applications on these resources. But it does not check service limits for resources.
Option D is incorrect as AWS CloudTrail is a logging service, recording activity made to AWS resources. But it does not check service limits for resources.
For more information on AWS Trusted Advisor, refer to the following URL:
https://aws.amazon.com/premiumsupport/technology/trusted-advisor/