The Robbers Study and the Jigsaw Classroom Underscore a Lesson

The Robbers study and the jigsaw classroom underscore a lesson confirmed by many other social psychology studies;that is,

A) increased contact between racial groups is sufficient to reduce prejudice.
B) increased contact between racial groups is rarely sufficient to reduce prejudice.
C) cooperative contact between groups is sufficient to reduce prejudice.
D) increased enjoyable contact between racial groups is sufficient to reduce prejudice.