Correct answer: Kd11...B:g2 2.O-O-O# 1...B:e2 2.K:e2# 1.Rb1?? zz 1...B:e2 2.K:e2# but 1...B:g2! 1.Rc1?? zz 1...B:e2 2.K:e2# but 1...B:g2! 1.