Which AWS service should the developer use?

Explanations:

AWS CodeBuild is a continuous integration service that automates the build and test phase of code. It is not designed for long-term code storage, versioning, or change tracking, making it unsuitable for sharing application code for feedback.

Amazon S3 is a scalable object storage service primarily used for storing and retrieving data. While it can store code, it does not provide built-in version control or change tracking features necessary for managing application code over time.

AWS CodeCommit is a fully managed source control service that enables teams to host secure and scalable Git repositories. It is designed for version control and batch change tracking, making it ideal for sharing application code with the team for feedback and collaboration.

AWS Cloud9 is a cloud-based integrated development environment (IDE) that allows developers to write, run, and debug code from a web browser. It does not provide version control or long-term code storage capabilities on its own, making it inadequate for the specified requirements.