A developer wants to share application source code with teammates for long-term storage, versioning, and grouped change tracking. Which AWS service is the appropriate choice?

AWS CodeCommit is a fully managed source control service that hosts secure Git-based repositories. It is the appropriate choice because it provides version control, allows developers to collaborate on code, and tracks changes over time, fulfilling all the requirements for long-term storage, versioning, and grouped change tracking. AWS CodeBuild is a fully managed continuous integration service that compiles source code, runs tests, and produces deployable software packages. It is not designed for source code storage or versioning. Amazon S3 is object storage and while it can store files, it lacks the version control and collaboration features essential for source code management. AWS Cloud9 is a cloud-based integrated development environment (IDE) that allows developers to write, run, and debug code, but it is not a source code repository itself.