Which of the following is not a way in which an author would develop a character?
a. have other characters discuss him of her.
b. write dialouge with the character and another character.
c. let the reader know what the character is thinking and feeling.
d. introduce new events involving the character.

A. have other characters discuss him of her.

Explanation:

Having characters speaking about the main one does move forward the protagonist's arc, since it does not add a relevant layer to his/her actions, reactions, thus, avoiding any possibility of development.

It must be done through him/herself in a variety of ways:

the answer to the question is a

answer:

a. "there, said he, there is something for you."

explanation:

"said he" should not have been part of what is in the dialogue.