Correct answer: Rf51...c4 2.Nd4# 1.Kd8?? zz 1...c4 2.Nd4# but 1...f5! 1.g7?? (2.g8Q#/g8B#) but 1...f5! 1.a3?? zz 1...c4 2.Nd4# but 1...f5! 1.a4?? zz 1...c4 2.Nd
