Muzafer Sherif and His Colleagues Created High Levels of Conflict

Muzafer Sherif and his colleagues created high levels of conflict between two groups of boys at a summer camp. The investigators improved inter-group relations by:

A) engaging boys from both groups in joint projects.
B) punishing boys from both groups.
C) dissolving the social hierarchies within both groups by removing their leaders.
D) introducing girls into both groups.