A functional relation using a reversal design calls for (minimally):

The correct answer would be - two alterations between baseline and a particular intervention.

Explanation:

Reversal designs are treatments design that is used to see or study the effect of specific treatment on the behavior of a single subject in any experiment or treatment method. In this setting, the single-subject are monitored for repeated times in order to establish a baseline level beahvior for a particular treatment.

It begins with a baseline or normal condition with no treatment, followed by two minimal alterations between the particular intervention.

answer; /// all of the above;