The correct answer is A. GitHub.
GitHub is a web-based hosting service for version control using Git. It is mostly used for computer code. It offers all of the distributed version control and source code management (SCM) functionality of Git as well as adding its own features. It provides access control and several collaboration features such as bug tracking, feature requests, task management, continuous integration, and wikis for every project.
OpenHash is a free and open-source distributed version control system. It is a command-line tool that allows users to track changes to files and directories. OpenHash is similar to Git, but it is not as widely used.
Git Bash is a command-line shell that allows users to interact with Git repositories. It is a Windows-based tool, but it can also be used on other operating systems. Git Bash is not a web hosting service.
Therefore, the correct answer is A. GitHub.