Final answer:
King advocated for non-violent resistance as a means to combat injustice, which became central to the Civil Rights Movement, using strategies like boycotts, sit-ins, and marches. The correct option is A.
Step-by-step explanation:
Dr. Martin Luther King Jr. advocated fighting injustice not with rage or compliance, but through non-violent resistance. He emphasized the efficacy of civil disobedience, a concept developed by figures like Henry David Thoreau and popularized in the struggle for Indian independence by Mohandas Gandhi. King's approach became a defining characteristic of the Civil Rights Movement, as seen in events such as the Montgomery bus boycott and the march on Washington.
Nonviolent strategies included boycotts, sit-ins, and marches, providing an alternative that did not involve armed conflict or passivity. Hence, the correct answer to what King suggested we should fight with is A. Non-violent resistance.