Left panel: cumulative distributions of projected distances from the center of M 31 of Sample A (long dashed line) and Sample B (dotted line) are compared with the distribution of all the confirmed M 31 clusters classified as old (GCs) (solid line). Right panel: the same comparison but for the distributions of three-dimensional distances from the center of M 31 (R_GC). For the whole sample we used as a proxy for R_GC.