The answer is: 3. It helps establish the idea that Didion's experiences in New York feel somewhat surreal to her now, like those of a character in a movie. <span> </span>
The phrase that indicated a lost in thought feel is the "Midnight shakes the memory". It means that his train of thought is going double time in the dark or at night.
All the other options seem like good reasons but are not as important as improving your overall skills (from my perspective at least). Hope this helps!
