Answer:
Cynthia is experiencing b. rebound effect as a result of her attempts at thought suppression.
Explanation:
Thought suppression is the conscious, motivated way of trying to erase or remove a certain thought. This conscious activity often leads to the rebound effect, which creates the opposite outcome; the individual will most likely keep thinking about this specific thought.
In this case, Cynthia's conscious act of trying not to think about a purple unicorn, leads to the rebound effect, in which she cannot stop thinking about it.
