The correct answer is Amazon CloudWatch Logs Insights. This service allows you to use a specialized query language to search, analyze, and visualize log data from your applications and AWS resources. It is particularly well-suited for ad-hoc log analysis and gaining operational insights. AWS CloudTrail is used for recording API calls and related events for your AWS account. Amazon Elasticsearch Service is for running Elasticsearch clusters at scale, providing search and data analytics capabilities. AWS Config is for assessing, auditing, and evaluating the configurations of AWS resources, not for querying log data for application insights.