This question is incomplete. The complete excerpt of the speech is here:
After contemplation, I conclude that this award which I receive on behalf of that movement is a profound recognition that nonviolence is the answer to the crucial political and moral question of our time – the need for man to overcome oppression and violence without resorting to violence and oppression. Civilization and violence are antithetical concepts. Negroes of the United States, following the people of India, have demonstrated that nonviolence is not sterile passivity, but a powerful moral force which makes for social transformation. Sooner or later all the people of the world will have to discover a way to live together in peace, and thereby transform this pending cosmic elegy into a creative psalm of brotherhood. If this is to be achieved, man must evolve for all human conflict a method which rejects revenge, aggression and retaliation. The foundation of such a method is love.
The correct answer is C. Hopeful
Explanation
In the previous excerpt from his Nobel Prize acceptance speech, Martin Luther King Jr expresses his ideas about the movement he led for nonviolence and how it allowed him to change aspects of society in which African Americans were radically segregated saying "this award ... is a profound recognition that non-violence is the answer to the political and moral question." Later, he projects this idea of peaceful struggle into the future by giving viewers a feeling of hope by saying "Sooner or later all the peoples of the world will have to discover a way to live together in peace." According to the above, it can be established that Martin Luther King Jr uses a hopeful tone because he projects his thoughts towards the future.
