Expository writing is used to convey factual information (as opposed to creative writing, such as fiction). It is the language of learning and understanding the world around us. If you've ever read an encyclopedia entry, a how-to article on a website, or a chapter in a textbook, then you've encountered examples of expository writing
So a or d but i'm leaning toward d
I had begun by tracing the Japanese characters with a pencil.
*begun is a past participle
Yes, you can say that! Or you can say “letter that contains advice” or “letter that provides advice.”
