What is unique about this rhetorical situation? How is this a once-in-a-lifetime opportunity for a speaker?

i think that the answer is a

this is d. hope this : d: d: d ; p

a. by showing how a character reacts to or interacts with his or her   surroundings

explanation:

the setting reveal information about a character by showing how a character reacts to or interacts with his or her   surroundings.

marian anderson was the first black aamerican to appear there. she played the role of ulrica in "a masked ball". anderson's appearance was mostly   symbolic, she was already past her prime as a singer, and she had made her succcess on the concert stage. in her first performance, she received a ten minutes ovation. the moment was considered momentous enough at the time to warrant a front page at the new york times story.

the singer wore an iridescent peasant blouse adorned with several beaded necklaces. the lights illuminated her features   from below, creating an aura of mysticism and darkening her expression in shadow. then, marian sang. when she hit the “a” note, she held it, and i knew that all   doubts about her skill must have melted away with that note.