If I understood your question correctly, then the answer is "it depends". Sometimes, individuals have a large impact on starting a war (think World War I where one individual caused the war to start), other times groups of people have also important roles in starting a war (think World War II).
I believe the answer is: Relationship building
understanding similarities and differences serve two important functions in relationship building. The first one is to create a sense of tolerance between different group of people. The second one is to help them achieve tolerable compromise during negotiation rather than conflict.
It was important to ignore the fears and rules that schools should not be segregated because back then, people thought blacks' were nothing and they treated them like dirt. Back then, black people were not allowed to learn with whites' because of social class
The answer is written by experts in their field of study.
I would have to go with The answer is A.
