Correct answer: Nb51...Nh3/Nf3/Ne2 2.Re2# 1...Rc7/d6 2.R:f4# 1...d5 2.Bc2# 1.Qe7+?? 1...Be5 2.R:f4# but 1...K:d4! 1.Ne2?? (2.Qd4#) 1.
