Correct answer: Nb51...d4 2.Bc4# 1...Nh6/Nf6 2.R:e7# 1...e:d6 2.Q:d6# 1.Kb7?? (2.Qc8#) 1...Nf6 2.R:e7# but 1...d4! 1.Bg6?? (2.Bf7#) 1...Nh6
