What details from a story best help develop the theme? readers' prior knowledge
the author's motivations for writing
descriptions of time and place
character motivation and plot

Character motivation and plot.

Explanation:

The character motivation and plot of the story are the most important details to show the theme.

Character motivation is the character's why. Why are they doing what they are doing? What inspires them? What motivates them?

Plot is the whole story. It is what is going on to all of the characters in the book, TV show, movie, etc.

Theme is the big idea of the story. It is usually one word, like "friends" or "work." It is the big thing for you to learn when you finish the story.

Now, character motivation and plot are the most important for the theme because they are the main things that drive the story. The author can insert aspects of the theme into the character's motivation and the plot of the story.

For example:

James was a tiny bit hungry for a sandwich. He had exactly enough money in his pocket to go to the sandwich shop and satisfy his tiny hunger.

(James' motivation is that he wants a sandwich because he is a little bit hungry.)

As James approached the sandwich shop, he came across a homeless person. The person was dirty and sitting against the wall of the shop. James walked past him and prepared to eat his delicious sandwich so he wouldn't be a tiny bit hungry anymore.

As James ordered his sandwich, he felt that the homeless person was more hungry than he was. He went outside and gave the person his sandwich.

(James' motivation changes by the end of the story. He no longer wants to satisfy his small need, but to help the homeless person who needs the sandwich more than him.)

The plot of the story is that James is hungry for a sandwich, he sees a homeless person, buys a sandwich, and gives it to the homeless person.

The theme of the story is gratefulness. James should be grateful that he has the freedom and ability to buy a sandwich, while the homeless person doesn't. He learns that by the end of the story.)

to inform the reader that the text will take a second look at the grimms’ original tales