What is the missing piece (marked "?") in this configuration of a normal chess game?

BLACK

WHITE
Notice that the Black King is in check by the White Rook.

(In reply to I'm stuck (spoiler) by Steve Herman)

Oh, one more thing.
5) It can't be a black bishop, because it has no way to move from its original starting square of f8, since it is blocked by two pawns.
So, the questionable piece is white.  It still looks like it could be a white rook, queen, bishop, or knight. 

Posted by Steve Herman on 2008-06-12 14:02:17