A Company runs continuous integration/continuous delivery (CI/CD) pipelines for its application on AWS CodePipeline. A Developer must write unit tests and run them as part of the pipelines before staging the artifacts for testing.
How should the Developer incorporate unit tests as part of CI/CD pipelines?

A. Create a separate CodePipeline pipeline to run unit tests
B. Update the AWS CodeBuild specification to include a phase for running unit tests
C. Install the AWS CodeDeploy agent on an Amazon EC2 instance to run unit tests
D. Create a testing branch in AWS CodeCommit to run unit tests