9: In which of the following cases is a person most likely to maintain
  attitude change?

    A: Johnny is threatened with severe punishment if he does not clean up his room.

    Incorrect.

Threatening Johnny with severe punishment, will not result in a long term attitude change.  Recall the "Robbie the Robot" study by Freedman (1965) (see Myers pg. 146), where children were told not to play with a specific toy (which was very desirable) and threatened with either mild or severe punishment.  While the experimenter was in the room, no child played with the toy.  Several weeks later, the children who were threatened with severe punishment played with the robot much more than the children who were threatened with mild punishment.  The reason hypothesized for this, is that the children who were threatened severely, had a very good reason not to play with the toy: they were severely threatened, while the children who received the mild threat, did not have a very good reason not to play with the toy, so their motivation for not liking the toy was internal.  In question 9, the same principles operate.  When Jonny is threatened severely to clean up his room, he do so, only because he is afraid of being punished, and not because he wants to.  Therefore, a severe punishment will not result in a long term attitude change.