The correct answer is B) Who is my audience?
The first practical question you should ask before you begin writing is "Who is my audience?"
This is part of the commonsense of the writer. It first has to know who its audience will be to use the proper language and do the correct kind of use of sources, depending on the purpose of its writing. Once this question has been answered, the writer must develop the plot of its story and the characters that are going to be included.