In the Festinger and Carlsmith (1959) Experiment on Turning Knobs

In the Festinger and Carlsmith (1959) experiment on turning knobs and telling the next subject that it was interesting, the researchers explained that the obtained results were due to:

A) post-decision regret
B) counter-attitudinal behaviour with justification
C) counter-attitudinal behaviour with insufficient external justification
D) counter-attitudinal behaviour with moderate threat
E) conflict before a decision