[fen]
3b2k1/5bp1/1p5p/p2N4/4pPP1/2P1P3/PB6/6K1 w - - 0 1
[/fen]

答案:
[pgn]
[Event "Tasc Chess Tutor"]
[Site "?"]
[Date "2015.07.22"]
[Round "?"]
[White "White"]
[Black "Black"]
[Result "*"]
[ChessCat "CHESSCAT 1.0"]
[FEN "3b2k1/5bp1/1p5p/p2N4/4pPP1/2P1P3/PB6/6K1 w - - 0 1"]
[PlyCount "1"]
[Setup "1"]

1. c4 *

[/pgn]