Correct answer: Qb71...a6 2.Qc5# 1.Kc4?? (2.Qb5#) but 1...a6! 1.Qc4?? zz 1...a6 2.Qc5#/Q:b4# but 1...Kb6! 1.Qd6?? zz 1...a6 2.Qc5#/Q:b4# but 1...K