What is the best definition for a dynamic character?

A. a character who undergoes an internal change over the course of the story

B. a character who does not change, despite the events of the story

C. one of the most important character's in the story, on whom the plot is centered

D. characters who do not play a pivotal role in the plot but still participate in the events of the story

P.S please do not answer if you did not take the same test or if you are not 100% sure your answer it correct.And also not because you want points. Thanks again <3