Answer:
It should be
C. What's the point of this piece of writing?
Explanation:
Because you are asking for the main idea, lets look at the answer choices:
A) Who said this quotation?
No - because that is one part of the writing, unless you are writing about a single person and the quote is said by he or her. But that doesn't matter, because you don't always need to know this piece of information.
B) Where can I read more on this subject?
No - because that is about another topic, not the single piece of writing.
C) What’s the point of this piece of writing?
Yes - because you are talking about the writing and that's the only that makes sense. Plus this will work for almost every kind of writing, narrative, fiction, informative, etc.
D) How long is this story or essay?
No - because it has nothing to do with the information that the piece of writing is providing.
