Answer:
third line is suitable for main theme
The monster threatens to hurt Victor's family if he doesn't help him.
I would say it's the Historian because they study history or the past and have to interpret it so they can figure out how to teach it or stop it from happening again.
The answers are
After that their manner changed a little toward me, although I was their friend against outsiders.
I was a friend, but I was never really one of them after they had read the citations, because it had been different with them and they had done very different things to get their medals.
These two are sentences because they are separated by peridods, commas only denote a smaller break in a long sentence. In these two sentences the author says that after learning how he got his medals the others were less enthused about them and started treating the narrator differently.
The answer for your question is d because it explains more details of the car than the other ones