For A, culture is not particularly related to most plots. For B, the medium of a story is the format in which you read it (book, magazine, ebook). For D, knowing where a story came from does not have anything to do with the length and complexity of the story
I'm not familiar with what context this is in, but i believe it is D because it's saying you will "bargain" with the calendar, meaning negotiate to try and get some more time
