With a multiple choice question like this, you can eliminate some answers right away. Just the phrase "character arc" tells you that this is something that refers to the character. Because the author of a story is not the same thing as the character in a story, you can eliminate answers C and D. Now, consider the word "arc." The word "arc" implies movement from point A to point B. It is not a straight line movement but a movement that implies a slow growth and change over time. Thus the phrase "character arc" refers to how a character grows and changes throughout the story, starting off one way and slowly becoming another way by the story's end. So, the correct answer here is B, "A character arc is how a character changes and grows over the course of a story.'
