Final answer:
Those who do the opposite of what is socially expected, to assert their freedom, are best illustrating cognitive dissonance, which involves psychological discomfort from conflicting behaviors and beliefs, leading to a change to alleviate this discomfort.
Step-by-step explanation:
Those who feel socially pressured sometimes assert their freedom by doing the opposite of what is socially expected. This best illustrates reactance, which is not directly listed among the provided options. However, the concept of asserting freedom can be related to the feeling of psychological discomfort that arises from a conflict in a person's behaviors, attitudes, or beliefs that runs counter to one's positive self-perception, known as cognitive dissonance. Cognitive dissonance can occur when there is a discrepancy between one's beliefs and one's actions, resulting in an uncomfortable feeling that leads to a change in attitude, behavior, or beliefs to reduce this discomfort. Of the choices given, cognitive dissonance theory (a) is the closest match, as it pertains to the internal conflict that could motivate a person to act contrary to social expectations in order to maintain a consistent self-image.