Recall That Participants in a Field Experiment by Raymond Reno

Recall that participants in a field experiment by Raymond Reno and his colleagues (1993) were more likely to properly dispose of a handbill left on their windshields when they saw a confederate pick up and dispose of a fast food bag.The researchers suggest that the role of the confederate in this study was to

A) let participants know what the descriptive norm was.
B) let participants know what the injunctive norm was.
C) make the norms salient to participants.
D) provide an audience to increase self-awareness.