The concept of a "self-fulfilling prophecy" is a psychological phenomenon where a prediction or expectation comes true simply because the person believes it will, and their resulting behaviors align to cause the prediction to occur. This concept is observable in the context of mass media where they create, shape, and reinforce expectations among audiences. Let's explore how each option fits or doesn't fit this scenario:

1. Professionalism: While mass media can promote professionalism by showcasing competent and ethical behavior, it primarily depends on the individual's response to such portrayals. It doesn't necessarily create a prophecy or a cycle.
2. Preference for corrupt practices: This option suggests that media could shape a sort of normalization of corruption. While media can sometimes negatively reinforce behavior by over-reporting corruption, leading to cynicism, it doesn't fulfill its predictions; instead, it highlights deviations from norms.
3. Political positivity: Like professionalism, political positivity requires a conscious effort from individuals and political environments. Media can advocate for it, but they don't necessarily create an expectation cycle that results in a self-fulfilling prophecy.
4. Self-fulfilling prophecy: This is the most apt option. Media create narratives that audiences often internalize. For example, if media repeatedly highlight the success of certain policies or individuals, it can lead public perception to construct a reality that brings about favorable outcomes simply through expectancy and collective behavior changes. Hence, media's power to suggest likely events can lead to the realization of these events through social behaviors aligning with these expectations.

Thus, the correct answer is Self-fulfilling prophecy, as mass media can instigate expectations within audiences, which in turn influences perceptions and actions that lead to the actual realization of these expectations.