In a multiple baseline design:

a.) Gaining a stable baseline is absolutely necessary in order to rule out the effects of the ABAB design b.) Gaining a stable baseline is not necessary to rule out effect of history,experience,and normal day-to-day fluctuation

c.) Gaining a stable baseline is necessary to rule out effect of between-subject variability Gaining a stable baseline is necessary to rule out effect of history,experience,and normal day-to-day fluctuation d.) Gaining a stable baseline is not necessary to rule out effect of between-subject variabilit