Which of the following statements concerning extinction is false?

Which of the following statements concerning extinction is false?
a. Extinction works best when coupled with the reinforcement of a desired substitute behaviour.
b. Behaviours learned under delayed or partial reinforcement schedules are more difficult to extinguish than those learned under continuous, immediate reinforcement.
c. Extinction can be successful in reducing an unwanted behaviour by removing the reinforcer of that behaviour.
d. Using the application of an unpleasant stimulus after an unwanted behaviour, extinction can reduce the probability of that behaviour occurring again.
e. Behaviours which are eliminated through extinction may reappear if they become positively reinforced again.