Question: In a Transparent end-to-end Packet-switched Streaming Service (PSS), what is the outcome when a PSS client sends a bookmark deletion request with only the UserID attribute set?
Option 1: Only the specified ContentURI's bookmarks are deleted for all users.
Option 2: All bookmarks belonging to the specified UserID are deleted.
Option 3: The deletion request is rejected due to insufficient attributes (missing ContentURI and BookmarkID).
Option 4: Only private bookmarks associated with a default ContentURI for the UserID are deleted.
Explanation: According to the bookmark deletion protocol in PSS, if only the attribute UserID is set in the 'BookmarkDeleteRequest', the server will proceed to delete all bookmarks that belong to the specified UserID. This highlights the importance of attribute specificity in managing bookmark deletions to ensure the correct scope of deletion is achieved.