4.A im pretty sure !! hope it helps
As for this problem concerning about a transition between sentences and paragraphs, the most probable and most likely to be the answer out of the options presented would be the third one which is a bridge.
A transition serves as a bridge between sentences and paragraphs. Though they create a divide between them, these transitions do not necessarily indicate that the divide is to cause to present that the two aren't connected to each other. A summary and introduction wouldn't do since a transition functions more and effectively between sentences and paragraphs.
I believe this depends solely on personal preference. A work of literature that you like may not be good to somebody else, so the way you feel about something makes it either good or bad. I believe I am pretty comfortable determining the quality of literature given that I have read a lot of books and have an overall grasp of each literary era throughout history. It can be easy to critique a text if you are knowledgeable enough about that particular era, style of writing, and general context, but it could also be quite difficult depending on the topic of that work.
A classic novel can be about any subject.
It doesn't have to be with a villain [Classic love stories]
You dont need a handsome protagonist.
So your answer is:
A doctrine is essential to writing a classic novel.