Correct answer: Kf11...K:c1 2.O-O# 1...R:g6/Rg8/Rf7/Rh7 2.Q:b2# 1...Nb5/Nc4 2.Q:c2# 1.B:g7?? (2.Q:b2#) 1...Nc4 2.Q:c2# but 1...B:g7!
