Syncing deleted bookmarks

This is more of a hypothetical question. Suppose that I have two desktops with Firefox syncing bookmarks between the two. Now I delete a bookmark in one of the computers. Then I sync again both computers. What should happen? Alternative 1: the bookmark deleted in one computer should also be deleted in the second computer? Alternative 2: the bookmark will be reloaded in the computer in which it was deleted? In either case, can someone explain how sync works and why alternative 1 or 2 is the correct one? Thanks.