The Diffusion of Innovation theory is associated with C) Everett Rogers. Everett Rogers, a professor of communication studies, developed the Diffusion of Innovation theory. This theory focuses on how new ideas, products, or innovations spread and are adopted by individuals and groups within a society or social system. It explains the factors that influence the adoption and diffusion process, such as the characteristics of the innovation, the communication channels, the social system, and the individual's attributes. Therefore, the correct answer is C) Everett Rogers.