Tone is the author's attitude toward the speech. Since we know that Dr. King was the author and presenter of the speech, this was one of inspiration, seriousness, hope, and encouraging. This is not to be confused with mood. Mood is your feelings from the text. So, while the tone may be one of hope, to say it was 'hopeful' would be a mood (if that is indeed what you are feeling when hearing it.)
to get a message across to the audience and such things as certain themes they want to raw attention to.
I would say answer A. It fits the best in my opinion.
pretty sure it would be sign up, like 99.9 percent sure
