Correct answer: Qg81...K:b7 2.Qc6# 1...R:c8 2.Q:c8# 1...B:b5 2.R:a7# 1...B:b7 2.R:a7#/N:b6# 1.N:b6+?? 1...K:b7 2.Qc6#/Qc7# but 1...a:b6!