The correct answer is - usual mode of constructing a story.
In his nonfictional essay, Philosophy of Composition, Poe wrote about how he wrote his famous poem The Raven and about the author's craft in general. He believed that many writers and poets had a wrong approach to creating their stories - they didn't analyze enough what they wanted to write about. If you read the essay, you will see Poe's painstaking details about writing his poem, the way all writers should pay attention to details.