Correct answer: Ra51...B:b2 2.Re1# 1.Qh1?? (2.Q:c1#) but 1...Kb1! 1.Re1?? (2.R:c1#) but 1...Kb1! 1.Nc3?? (2.Qa8#/Ra5#) 1...Be3 2.Ra5#
