I believe the answer would be D: a current study on the effects of stress on the body published by a medical journal.
Hope this helps.
While I have never read the book (because it is historically inaccurate - so don't get too sad, because it never could have happened), there are many words that would signal a flashback. Flashbacks are a time of reflection, so there are many past tense verbs used. You may also see things like, "Back in my day...", "As I think back...", "When I was a young boy...", "As I remember...".
1. Would be third-person.
No we, I, us, etc.
I'd assume they are referring to the metaphor of "you" being a "gray cat" or "quiet street."