Why Did Participants in an Experiment Conducted by Ellen Berscheid

Why did participants in an experiment conducted by Ellen Berscheid and her colleagues (1968) derogate their victims unless they thought they would switch roles with the victim and receive shocks themselves? In this case,participants

A) reasoned that the victim would have a chance to even the score.
B) were motivated to justify their cruel behaviors.
C) experienced maximal dissonance,and convinced themselves that the victim deserved it.
D) chose to become a victim,too,in order to make the situation more fair.