Definitely C here. git reset HEAD devcoreg13642911.jpg takes the file back out of the staging area but doesn't delete it, so it's still in your working directory. That's how you keep your work without including it in the next commit. Pretty standard process in git, let me know if anyone's seen another method for just unstaging.
git reset HEAD [file] is the only real way to unstage without deleting anything, just like in recent exam versions. D is a trap, it's for undoing commits, not unstaging. Open to corrections if I'm missing something.git reset HEAD [file] is the exact way to unstage without touching the actual file. Other options either don’t exist or do something else. Pretty sure it’s what they want here, but open to other takes.