A Market Researcher Showed a New Brand of Blue Jeans

A market researcher showed a new brand of blue jeans to several groups of students and asked the students to rate the quality of the jeans. Two weeks later, the researcher showed the same students a television advertisement featuring super model Cindy
Crawford wearing the new brand of jeans. The marketer asked the students to once again rate the quality of the jeans. The marketer predicted that after viewing the
Advertisement, the students' ratings of the new jeans would be more positive than their original ratings. In this experiment, students' ratings of the new blue jeans served as
The:

A) outside factors.
B) dependent variable.
C) secondary data.
D) independent variable.