Final answer:
The correct option to stop tracking a file in Git after running the initial snapshot on the master branch is 'D. Cease, Halt'. Use the command 'git rm --cached ' to untrack the file, followed by updating the .gitignore file and committing the changes.
Step-by-step explanation:
If you ran the initial snapshot on the master branch and later realized that a .gitignore file should have included a reference to ignore tracking of certain files like a package.xml, and now you want to cease tracking the package.xml, you will need to use a specific Git command.
To stop tracking a file that is currently tracked by Git, you should use the command:
This command removes the file from the index, staging the deletion, but keeps the local file unchanged. After running this command for the package.xml, you would then need to commit the changes to update the repository. Moreover, remember to update the .gitignore file to ensure Git continues to ignore the package.xml in future commits.
The correct option from the question is D. Cease, Halt.