All of the options provided can effectively illustrate how genre affects the theme of a text, but if you had to choose one that directly addresses the influence of genre on theme presentation, the most comprehensive response would be:
Genre affects which themes can be presented in the story.
This is because different genres often have conventions and expectations that guide the types of themes that are explored. For example, a romance novel might focus on themes of love and relationships, while a horror story could delve into themes of fear and survival.