Correct answer: O-O-O1...b:c2 2.Ra3# 1.Nc3?? (2.R:e4#) but 1...K:d4! 1.Nd6?? (2.R:e4#) but 1...K:d4! 1.Na3?? zz 1...b:c2 2.N:c2# but 1...K:d4! 1.R