According to the authors, the limitations of the design do not allow other variables, such as , to be ruled out as possible influences on the drug and alcohol use outcomes of 12-step participants.
a. maturation confound
b. time confound
c. motivational confound
d. participation confound

The answer is "pathos".

Explanation:

It is possible to persuade the audience by deliberately evoking certain emotions to make them feel the way the writer wants readers to feel. It is also referred to as the result of a speaker's emotional appeal, the audience feels a certain way. The statement's goal is to evoke a favorable emotional reaction in the audience toward the statement's goal. Evoking feelings is the most effective way to produce pathos.