Why Is Variability in the Data at Baseline Assessment Problematic

Why is variability in the data at baseline assessment problematic in single-case designs?

A) Because performance at baseline indicates whether the treatment will be effective for the given participant
B) Because performance at baseline allows the investigator to generalize the findings to others in the population
C) Because performance at baseline is used to predict future performance and variability makes prediction difficult
D) Because performance at baseline is used to predict past performance and variability makes prediction difficult