In the ABC Single-Subject Design

In the ABC single-subject design:

A) there are three treatment periods in which two treatments are similar
B) a new treatment in addition to the first treatment or a new component is added to the first treatment in order to establish whether the first treatment was better than the baseline and whether the second treatment was better than the first treatment
C) the single measurement before treatment begins is followed by measuring the client several times during the second treatment period
D) a new treatment is added to the first treatment followed by a second baseline period