Which AWS service should the company use to meet this requirement?

Explanations:

AWS CloudTrail is primarily used for logging API calls and monitoring account activity. It does not provide quota monitoring or alerts.

AWS Trusted Advisor offers insights into your AWS resources, including checks for service limits. It can provide alerts when you approach your service quotas, making it the best option for this requirement.

AWS Config is used for monitoring configuration changes and compliance. It does not directly provide service quota monitoring or alerts related to resource limits.

Amazon Inspector is a security assessment service that helps improve the security and compliance of applications. It does not offer functionality for monitoring service quotas.