In the "Robber's Cave" Study Described in Your Text,students at a Summer

In the "Robber's Cave" study described in your text,students at a summer camp were separated into two groups,the "Rattlers" and the "Eagles." The students ended up calling the members of the other group derogatory names,raiding their cabins,and fighting.How did the researchers explain the animosity between the two groups?

A) Rattlers tended to be athletic; Eagles had more intellectual interests.
B) The Rattlers were chosen from more impoverished environments than the Eagles.
C) The two groups had been competing against each other.
D) The students were away from home, which increased their aggressiveness.