When an Intervention in a Single-Subject Design Is Expected to Have

When an intervention in a single-subject design is expected to have an effect in the same direction as a baseline trend (either positive or negative) ,the researcher should

A) provide other evidence showing an effect of the treatment that flattens the baseline.
B) provide other evidence showing an effect of the treatment that causes the baseline to change direction at least twice.
C) use additional means of evaluation such as asking for subjective evaluations from others familiar with the individual.
D) use graphical analysis to prove that the change from the baseline trend is a "marked" change in the behavioral recorD.