The effective use of extinction is complicated by

a. the fact that it involves alternating periods of presenting and withholding the reinforcer.
b. extinction bursts.
c. the fact that it takes some time to complete relaxation training.
d. the fact that the client always has direct control of the reinforcer maintaining his or her
undesirable behavior.
e. an extensive history of reinforcement of the undesirable behavior.

b. extinction bursts.