When changes are committed to a source repository configured in an AWS CodePipeline, an Amazon CloudWatch Event (now part of Amazon EventBridge) is generated. AWS CodePipeline uses a CloudWatch Events rule to detect these source changes (e.g., a push to an AWS CodeCommit repository). This event acts as a trigger, automatically starting a new execution of the pipeline. This event-driven mechanism ensures that the CI/CD process is initiated immediately upon a code change, facilitating continuous integration and delivery.

A. Cloud Config is used for auditing and evaluating AWS resource configurations, not for triggering pipelines from code commits.

B. BinSkim is a static analysis tool for binaries; it is a tool used within a pipeline, not an event that triggers it.

D. Security Hub aggregates security findings from various AWS services; it does not trigger pipeline executions based on repository changes.

1. AWS Documentation. (2023). Start a pipeline execution in CodePipeline. AWS CodePipeline User Guide. Retrieved from https://docs.aws.amazon.com/codepipeline/latest/userguide/pipelines-start.html. (See the section "Start a pipeline automatically with source code changes," which states, "We recommend you use Amazon CloudWatch Events to detect the latest change and then start your pipeline.")

2. AWS Documentation. (2023). Tutorial: Create a simple pipeline (CodeCommit repository). AWS CodePipeline User Guide. Retrieved from https://docs.aws.amazon.com/codepipeline/latest/userguide/tutorials-simple-codecommit.html. (Step 2 mentions that for CodeCommit, "a CloudWatch Events rule is created to detect changes and start the pipeline.")