Answer:
b. after telling people that the experiment was interesting, participants in the $1 condition tended to express a more favorable attitude toward the experiment.
Explanation:
In the experiment carried out by Festinger and Carlsmith, the participants are told it was a fun experiment. It will be found that participants that took $1 will have a more positive attitude to the experiment because they are not motivated by the money given but want to have fun while performing the experiment. They are motivated by intrinsic forces.
On the other hand those that got $20 are more interested in the money and will just perform the task to get the reward. They are motivated by extrinsic factors (money),