The correct option is A Vivid expression of how she views words
At the very beginning of the passage the author mentions that words have a "particular power" for her. She goes on to recall how this one time, when she was leafing through a Native American poems book before a class, she was "struck by a phrase from the preface" Then she quotes the phrase. In this context, we can conclude that the quote was used to present the power that words have for her and how she views words. Thus A is the answer.