The reverend martin luther king jr. insisted that civil disobedience aimed at ending discrimination in the south should be conducted

In the blank you could use "peacefully" or "in a nonviolent manner."

Martin Luther King Jr. was known for his approach to bringing social, political, and legal changes in a peaceful way. MLK believed these methods would show that African-Americans had strong moral character and deserved the same treatment as everyone else. These nonviolent methods include:
1) Sit-in's
2) Marches
3) Boycotts

I'll go with that