Which of the Following Best Summarizes the Findings from Sherif's

Which of the following best summarizes the findings from Sherif's boys' summer camp experiment?

A) Just putting the two groups in contact with each other reduced the fighting.
B) Having the two groups work on tasks with shared goals reduced the fighting.
C) Neither strategy reduced the fighting, as these groups had a long history of fighting.
D) Hostility was only reduced while they were working toward a shared goal.