I believe it is Irony but I'm not completely sure.
#1) How does the voice affect the characterization and credibility of the text?
Answer: The way that the voice affect the characterization of the text is by giving the story a humorous tone. Also it affects the credibility of the text by overreacting and exaggerating which as a result makes the text not much credible.
I hope it helps, Regards.
I would say A, and I think you mentioned Independence, but if you didn't then it is D