A researcher wants to know if 2nd graders and 8th graders differ in their preferences for TV shows. The researcher has ten 2nd graders and ten 8th graders at Smith Elementary watch "Kenny the Clown" and "Action Rangers". Ten 2nd graders and ten 8th graders at Wilson Elementary watch the same two shows. Then each child rates how much they liked each show on a scale from 1-10. At both schools, Kenny the Clown is shown on a small television set in the cafeteria and Action Rangers is projected on the large screen in the school auditorium. The mean ratings for 2nd graders: Kenny the Clown, 8.4: Action Rangers, 4.8. The mean ratings for 8th graders: Kenny the Clown, 6.7; Action Rangers, 3.1. Which of the following best describes this research design?
a) 2x2 independent groups factorial design
b) 2x2 mixed factorial design
c) 2x2 repeated measures factorial design
d) 2x2x2 independent groups factorial design