The Results of a Study by Sherif at a Summer

The results of a study by Sherif at a summer boys' camp suggest that an effective way to reduce prejudice is to

A) prevent people from interacting with those whom they are prejudiced against.
B) allow prejudiced groups to compete with each other in friendly competition.
C) require prejudiced groups to work cooperatively toward some common goal.
D) lecture to prejudiced groups about the harmful effects of prejudice.