Why does the author include these sentences?

the other force is one of bitterness and hatred, and it comes perilously close to advocating violence. it is expressed in the various black nationalist groups that are springing up across the nation.

a) to predict the future of his group’s actions

b) to recall the harsh actions of law enforcement

c) to encourage understanding of black nationalists

d) to provide a contrast to his group’s nonviolent efforts

d) to provide a contrast to his group’s nonviolent efforts.

The author states that various black nationalist groups are springing up across the nation. He also states that these represent the force of "bitterness and hatred" and that they come "perilously close to advocating violence." It is obvious from the passage that the author disagrees with these groups and believed them to be violent and bitter. It is likely that he wants to provide a contrast to his own group's nonviolent efforts.

i think the answer is either c or d

im thinking d might make more sense though

sorry if im wrong