The choice to present a story through the medium of radio can most affect an audience's perception of it in the following way:
B. Emotional music can sway an audience's emotions.
Since we are talking about a story which the audience will exclusively listen to, an audio element such as emotional music can certainly affect the audience's perception of it, because it adds to the listening experience. In fact, that would be a vital element, since there would be no visual aids to help convey whatever messages or feelings the author of the story wanted the audience to experience.