I think it is A because.....
In composition, expository writing is also called exposition, informational writing, and informative writing.
As one of the four traditional modes of discourse, expository writing may include elements of narration, description, and argumentation, but unlike creative writing or persuasive writing, its primary goal is to deliver information about an issue, subject, method, or idea.
What do you need help with ?
The last sentence is very formal. It does not contain the first person pronoun (I or me) which is one of the marks of informal writing. Having given you the answer, may I say that question is almost totally irrelevant. I do not mean that you are at fault for having asked it. You are only asking for an answer, and that was given.
What I really mean to say is that I hope you get to read more of Amy Tan's remarks about her mother's English. They are astonishing observations and should be required reading by every student taking English or American Literature.
Thank you for posting this question. I didn't there was more to Tan's essay about her mother's English that I didn't know about, and I'm glad to know there is more.
