Correct answer: Be51...c3 2.Rf4# 1.Nc8?? zz 1...c3 2.Rf4# but 1...Ka4! 1.Nd7?? zz 1...c3 2.Rf4# but 1...Ka4! 1.Na4?? zz 1...c3 2.Rf4# but 1...K:
