In a Graph of the Results from Multiple-Baseline Design Using

In a graph of the results from multiple-baseline design using two participants,which of the following features justifies a conclusion that the treatment causes changes in behavior?

A) the size of the change in behavior each time the treatment is introduced
B) the time delay between the introduction of the treatment and the first change in behavior for each participant
C) the return to baseline behavior when the treatment is withdrawn for both participants
D) demonstrating that the same change in behavior occurs when the treatment is introduced at different times for the two participants