Correct answer: Nd31.Rc7?? zz 1...Kd1 2.Bg4# but 1...Kf1! 1.Rf7?? (2.Bg4#) but 1...Kd1! 1.Rg7?? zz 1...Kf1 2.Bc4# but 1...Kd1! 1.Nf3??
