Sherif Found in His Experiment at Robber's Cave That Which

Sherif found in his experiment at Robber's Cave that which of the following conditions needed to exist before status hierarchies developed among the boys in a particular peer group?

A) They needed to engage in competitive games with each other.
B) They needed to engage in cooperative activities with each other.
C) They needed to be given unequal rewards.
D) None of the above; status hierarchies emerged naturally.