How Did Muzafer Sherif Reduce the Tension at the Camp

How did Muzafer Sherif reduce the tension at the camp between the Eagles and Rattlers?

A) After all the competition between the boys had been created, the head counselor had to sit the boys down and tell them that it was an experiment. The little speech saved the day.
B) They had a big campfire, and all the boys had a good time.
C) They deliberately broke the water supply system, so it took all the boys in both groups working together to fix it.
D) The situation got out of hand. The parents had to come and get the boys sooner than was expected.