Correct answer: Nf41.c4?? (2.Qf6#) but 1...Kd4! 1.Bf5?? zz 1...f:g6/f6 2.Qe6# but 1...K:f5! 1.Nf6?? zz 1...Kf4 2.Qe4# but 1...f:g6! 1.Nf4! zz 1...K<