Which of the Following Questions Would a Social Psychologist Be

Which of the following questions would a social psychologist be least likely to study?

A) What kinds of persuasion techniques are the most effective in product advertising?
B) What are the most important qualities people look for in a romantic partner or friendship?
C) Why do people sometimes behave differently in a group setting than they do on their own?
D) Have attitudes toward gay marriage in the U.S. changed in the last five years?