Its to evoke a specific emotional state in the reader.
The authors theme;what message is he trying to get across to the reader? The authors style;what elements of literature does he use to make the story understanding and interesting. Elements are: Imagery, Simile, Metaphor, Irony, Figurative language, Rome Sceme, Point of View etc..
The appositive phrase is not Maya Lin, like the comment above me stated, but it is B) Chinese-American.
An appositive phrase is usually separated from the rest of the sentence by commas, and it describes the subject, which here is Maya Lin.
