a) Consider an instance of the stable marriage problem given by the ranking matrix. A B C a 1,2 3,3 2,1 2,1 1,2 3,3 Y 3,3 2,1 1,2 For each of its marriage matchings, indicate whether it is stable or not. For the unstable matchings, specify a blocking pair. For the stable matchings, indicate whether they are man-optimal, woman-optimal, or neither. (Assume that the Greek and Roman letters denote the men and women, respectively.) (10 p.)