I am absolutely sure that thw best summary of "Martin Luther King Jr.: He Showed Us the Way\" by César Chávez is being revealed by the second option represented above. Only this one really makes sense and propely refers to the purpose of the story.
B. Nonviolence brings together people of good conscience, and its benefits are overwhelmingly positive compared to any act of violence.
The answer is It tells the reader what will be discussed.
