Correct answer: Ra31...Nd1/Rb1+ 2.Bb1# 1...Nd5 2.Kd2#/B:b2#/Bb1# 1...Ne4/Nb1 2.B:b2#/Bb1# 1...Nb5 2.Kd2#/B:b2# 1...N:a2+ 2.Kd2#
