Represents Within-Cells Error Variation in the Partitioned Score of a Subject

represents within-cells error variation in the partitioned score of a subject in a two-factor between-subjects analysis of variance.

A) $\bar { X } _ { A B } - \bar { X } _ { G }$
B) $X - \bar { X } _ { A B }$
C) $X - \bar { X } _ { G }$
D) $X + \bar { X } _ { A B }$