Final answer:
The Festinger and Carlsmith (1957) study found that cognitive dissonance arose among subjects who were paid only $1 to lie, as the small reward did not align with their behaviors, leading to greater dissonance.
Step-by-step explanation:
The findings of the Festinger and Carlsmith (1957) study, which related to the concept of cognitive dissonance, can be outlined as follows: Option (c), 'the discrepancy between telling the next participants that the experiment is interesting and being paid $1 leads to cognitive dissonance.' This is because the subjects who were paid only $1 to lie about the experiment being interesting experienced a greater discrepancy between their actions and their beliefs, which was not sufficiently justified by the payment, causing them to experience cognitive dissonance. In contrast, those who were paid $20 had an adequate external justification for their actions, thereby reducing the experience of dissonance.